From 3c606c9f5829962178236eb8060ffff55e9f9176 Mon Sep 17 00:00:00 2001
From: Igor Velkov <325961+iav@users.noreply.github.com>
Date: Thu, 5 Mar 2026 07:14:01 +0200
Subject: [PATCH 1/3] docs: add extensions reference list and update navigation

- Add Developer-Guide_Extensions-List.md: alphabetical reference of
  all 60+ official extensions with short descriptions
- Rename 'Extensions' nav entry to 'Extensions Framework' to better
  reflect the page content (framework concepts, not extension catalog)
- Fix trailing whitespace on Netconfig nav entry

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 docs/Developer-Guide_Extensions-List.md | 429 ++++++++++++++++++++++++
 mkdocs.yml                              |   5 +-
 2 files changed, 432 insertions(+), 2 deletions(-)
 create mode 100644 docs/Developer-Guide_Extensions-List.md

diff --git a/docs/Developer-Guide_Extensions-List.md b/docs/Developer-Guide_Extensions-List.md
new file mode 100644
index 00000000..d3d09bdb
--- /dev/null
+++ b/docs/Developer-Guide_Extensions-List.md
@@ -0,0 +1,429 @@
+# Extensions Reference
+
+Alphabetical reference of all official Armbian build framework extensions.
+Extensions live in the `extensions/` directory of the build repository.
+
+To enable one or more extensions:
+
+```bash
+./compile.sh BOARD=... BRANCH=... ENABLE_EXTENSIONS="ext-name,another-ext"
+```
+
+Extensions with dedicated documentation pages are linked below.
+All others are documented by a short description and key parameters.
+
+---
+
+## allwinner-kernel-bump
+
+Bumps the kernel version for Allwinner-based boards.
+
+---
+
+## amlogic-fip-blobs
+
+Fetches Amlogic FIP (Firmware Image Package) blobs needed for bootloader assembly on Amlogic SoCs.
+
+---
+
+## apa
+
+Enables Armbian Package Archive (APA) in the target image by default.
+
+---
+
+## arm64-compat-vdso
+
+Enables 32-bit compat vDSO for arm64 kernels. Requires a 32-bit ARM cross-compiler for GCC builds (`gcc-arm-linux-gnueabi` or custom `CROSS_COMPILE_COMPAT`). For clang builds uses the built-in LLVM backend.
+
+---
+
+## armbian-config
+
+Installs `armbian-config` from the Armbian GitHub repository into the image.
+
+---
+
+## armbian-live-patch
+
+Installs the Armbian Live Patch systemd service into the BSP package.
+
+---
+
+## bcmdhd
+
+Builds the Broadcom BCM WiFi (`bcmdhd`) driver as a DKMS kernel module. Requires working kernel headers.
+
+---
+
+## bcmdhd-spacemit
+
+Builds the Broadcom BCM WiFi driver for SpacemiT platforms as a DKMS kernel module.
+
+---
+
+## bluetooth-hciattach
+
+Sets up Bluetooth via `hciattach` for boards that require serial attachment.
+
+---
+
+## c-plus-plus-compiler
+
+Adds a C++ compiler to host build dependencies. The C++ compiler is no longer included by default; enable this extension when the build requires it.
+
+---
+
+## ccache-remote
+
+Enables ccache with a remote storage backend (Redis or HTTP/WebDAV) for sharing the compilation cache across multiple build hosts. Requires ccache 4.4+.
+
+---
+
+## cleanup-space-final-image
+
+Runs `zerofree` and cleans APT caches in the final image to reduce disk footprint.
+
+---
+
+## cloud-init
+
+Installs and configures cloud-init in the target image.
+
+---
+
+## detect-unused-extensions
+
+Developer/testing extension: a hook honeypot used to verify the extension framework works correctly.
+
+---
+
+## fake-vcgencmd
+
+Installs a fake `vcgencmd` stub for Raspberry Pi software compatibility on non-Pi boards.
+
+---
+
+## fs-btrfs-support
+
+Adds Btrfs filesystem support: host build tools and image packages. Auto-enabled when `ROOTFS_TYPE=btrfs`.
+
+---
+
+## fs-cryptroot-support
+
+Adds LUKS/cryptroot support. Auto-enabled when `CRYPTROOT_ENABLE=yes`.
+
+---
+
+## fs-f2fs-support
+
+Adds F2FS filesystem support. Auto-enabled when `ROOTFS_TYPE=f2fs`.
+
+---
+
+## fs-nilfs2-support
+
+Adds NILFS2 filesystem support. Auto-enabled when `ROOTFS_TYPE=nilfs2`.
+
+---
+
+## fs-xfs-support
+
+Adds XFS filesystem support. Auto-enabled when `ROOTFS_TYPE=xfs`.
+
+---
+
+## gen-sample-extension-docs
+
+Generates extension hook documentation and a sample extension file. Useful for extension developers.
+
+---
+
+## grub
+
+Standard GRUB bootloader setup for UEFI-capable boards. Supports `DISTRO_GENERIC_KERNEL` mode.
+
+---
+
+## grub-riscv64
+
+GRUB bootloader setup for RISC-V 64-bit boards.
+
+---
+
+## grub-with-dtb
+
+GRUB with device tree blob (DTB) embedding support.
+
+---
+
+## gxlimg
+
+Builds the `gxlimg` tool used for creating Amlogic bootable images.
+
+---
+
+## image-output-abl
+
+Converts the output image to ABL (Android Boot Loader) format using `mkbootimg`.
+
+---
+
+## image-output-oowow
+
+Creates an image compatible with the OOWOW recovery system for Khadas boards.
+
+---
+
+## image-output-ovf
+
+Produces an OVF (Open Virtualization Format) archive for use in VMware and other hypervisors. Depends on `image-output-qcow2`.
+
+---
+
+## image-output-qcow2
+
+Produces a qcow2 image suitable for QEMU/KVM virtualization.
+
+---
+
+## image-output-utm
+
+Produces a UTM-compatible image for macOS virtualization. Depends on `image-output-qcow2`.
+
+---
+
+## image-output-vhd-azure
+
+Produces a VHD image for use with Microsoft Azure.
+
+---
+
+## image-output-vhdx
+
+Produces a VHDX image. Depends on `image-output-qcow2`.
+
+---
+
+## initramfs-usb-gadget-ums
+
+Adds USB Mass Storage (UMS) gadget support to the initramfs, allowing the board to expose its storage over USB.
+
+---
+
+## jethub-burn
+
+Adds JetHub device flashing support to the build.
+
+---
+
+## kernel-rust
+
+Enables Rust language support in the Linux kernel (`CONFIG_RUST`). Installs a rustup-managed toolchain into `${SRC}/cache/tools/rustup/` and configures all required make parameters.
+
+---
+
+## kernel-version-toolchain
+
+Adds the compiler name and version (e.g. `gcc13.3`, `clang20.1`) to the kernel artifact version string, ensuring cache invalidation when the toolchain changes.
+
+**Variables:** none (auto-detects from `KERNEL_COMPILER`).
+
+---
+
+## lowmem
+
+Applies Armbian optimizations for low-memory boards (reduced parallelism, swap configuration, etc.).
+
+---
+
+## lsmod
+
+Applies `localmodconfig` based on an lsmod output file to build a minimal kernel. Place the lsmod file in `userpatches/lsmod/<board>.lsmod`. **Variable:** `LSMOD` (defaults to `$BOARD`).
+
+---
+
+## lvm
+
+Adds LVM (Logical Volume Manager) support to the image.
+
+---
+
+## marvell-tools
+
+Fetches Marvell Armada A3700 build tools, DDR library, and binary blobs needed for bootloader assembly.
+
+---
+
+## mesa-vpu
+
+Installs Mesa 3D and VPU/Chromium acceleration packages. On Ubuntu: full 3D + 4K VPU. On Debian: 3D only.
+
+---
+
+## mtkflash
+
+Adds MediaTek device flashing tool support to the build.
+
+---
+
+## net-chrony
+
+Installs the `chrony` NTP daemon for network time synchronization.
+
+---
+
+## net-network-manager
+
+Installs NetworkManager and Netplan for network interface management.
+
+---
+
+## net-systemd-networkd
+
+Installs systemd-networkd and Netplan for network interface management.
+
+---
+
+## net-systemd-timesyncd
+
+Installs `systemd-timesyncd` for network time synchronization.
+
+---
+
+## nicod-armbian-gaming
+
+Gaming-oriented Armbian image configuration.
+
+---
+
+## nomod
+
+Builds the kernel with all modules disabled (`localmodconfig` with empty lsmod). Produces a non-working kernel — intended for rapid kernel build/packaging tests only.
+
+---
+
+## nvidia
+
+Builds the Nvidia proprietary kernel module via DKMS. Not available in minimal images.
+
+---
+
+## odin2-preset-firstrun
+
+Applies preset first-run configuration specific to the Odin2 gaming device.
+
+---
+
+## preset-firstrun
+
+Applies preset network and first-run configuration to the image (writes `.not_logged_in_yet`).
+
+---
+
+## radxa-aic8800
+
+Builds the Radxa AIC8800 WiFi driver as a DKMS kernel module. Requires working kernel headers.
+
+---
+
+## rkbin-tools
+
+Fetches Rockchip binary tools (`rkbin`) from the configured git repository. **Variables:** `RKBIN_GIT_URL`, `RKBIN_GIT_BRANCH`.
+
+---
+
+## rkdevflash
+
+Adds Rockchip device flashing tool support to the build.
+
+---
+
+## sunxi-tools
+
+Adds a 32-bit ARM cross-compiler to host dependencies for Allwinner (sunxi) builds. Only required outside Docker.
+
+---
+
+## syterkit-allwinner
+
+Writes the SyterKit bootloader image to the appropriate offset in the Allwinner output image.
+
+---
+
+## ti-debpkgs
+
+Installs Texas Instruments packages from the official TI Debian package repository.
+
+---
+
+## u-boot-menu
+
+Configures the U-Boot boot menu for boards that support it.
+
+---
+
+## uboot-btrfs
+
+Enables Btrfs filesystem support in U-Boot (`CONFIG_CMD_BTRFS`).
+
+---
+
+## uefi-edk2-rk3588
+
+Integrates UEFI EDK2 firmware for Rockchip RK3588 boards.
+
+---
+
+## ufs
+
+Creates a UFS-sector-aligned image. Requires Debian Trixie (13) or newer as the build host. Set `DOCKER_ARMBIAN_BASE_IMAGE=debian:trixie` when building in Docker.
+
+---
+
+## uwe5622-allwinner
+
+Builds the UWE5622 WiFi driver for Allwinner-based boards.
+
+---
+
+## v4l2loopback-dkms
+
+Builds the `v4l2loopback` virtual camera kernel module via DKMS. Not available in minimal images.
+
+---
+
+## vmware-vm
+
+Creates a VMware-compatible image (VMDK + OVF) with VMware tools installed. Depends on `image-output-ovf`.
+
+---
+
+## wayland-sessions-mask
+
+Masks Wayland desktop session entries for boards with limited or unstable Wayland support.
+
+---
+
+## watchdog
+
+Installs the `watchdog` daemon and enables `CONFIG_WATCHDOG` / hardware watchdog device support in the kernel.
+
+---
+
+## xorg-lima-serverflags
+
+Configures X.Org server flags for the Lima open-source GPU driver.
+
+---
+
+## yt6801
+
+Builds the Motorcomm YT6801 Ethernet controller driver as a DKMS kernel module. Requires working kernel headers.
+
+---
+
+## zfs
+
+Builds ZFS kernel module and userspace tools via DKMS. Requires working kernel headers.
diff --git a/mkdocs.yml b/mkdocs.yml
index 6b7f2722..4a04269f 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -147,7 +147,7 @@ nav:
         - 'Media': 'User-Guide_Armbian-Software/Media.md'
         - 'Monitoring': 'User-Guide_Armbian-Software/Monitoring.md'
         - 'Music': 'User-Guide_Armbian-Software/Music.md'
-        - 'Netconfig': 'User-Guide_Armbian-Software/Netconfig.md'        
+        - 'Netconfig': 'User-Guide_Armbian-Software/Netconfig.md'
         - 'Printing': 'User-Guide_Armbian-Software/Printing.md'
         - 'VPN': 'User-Guide_Armbian-Software/VPN.md'
         - 'Web hosting': 'User-Guide_Armbian-Software/WebHosting.md'
@@ -161,7 +161,8 @@ nav:
         - 'Extensions Hooks' : 'Developer-Guide_Extensions-Hooks.md'
         - 'Building with Multipass' : 'Developer-Guide_Building-with-Multipass.md'
         - 'Building with Docker' : 'Developer-Guide_Building-with-Docker.md'
-        - 'Extensions' : 'Developer-Guide_Extensions.md'
+        - 'Extensions Framework' : 'Developer-Guide_Extensions.md'
+        - 'Extensions List' : 'Developer-Guide_Extensions-List.md'
 
   - 'ARMBIAN COMMUNITY' :
         - 'Forums' : 'Community_Forums.md'

From c82cee37948ed374f0c9f03cd3d8afb9212c4514 Mon Sep 17 00:00:00 2001
From: Igor Velkov <325961+iav@users.noreply.github.com>
Date: Thu, 5 Mar 2026 08:49:28 +0200
Subject: [PATCH 2/3] docs: add kernel-rust extension dedicated page

Add Developer-Guide_Extension-kernel-rust.md with full documentation:
motivation (upcoming Rust-dependent drivers), quick start, parameters,
toolchain cache, extensibility, and implementation notes.

Update Extensions List to link to the new page.
Add kernel-rust to mkdocs.yml navigation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 docs/Developer-Guide_Extension-kernel-rust.md | 118 ++++++++++++++++++
 docs/Developer-Guide_Extensions-List.md       |   2 +
 mkdocs.yml                                    |   1 +
 3 files changed, 121 insertions(+)
 create mode 100644 docs/Developer-Guide_Extension-kernel-rust.md

diff --git a/docs/Developer-Guide_Extension-kernel-rust.md b/docs/Developer-Guide_Extension-kernel-rust.md
new file mode 100644
index 00000000..9e7b15c1
--- /dev/null
+++ b/docs/Developer-Guide_Extension-kernel-rust.md
@@ -0,0 +1,118 @@
+# Extension: kernel-rust
+
+The Linux kernel has been gaining Rust support since version 6.1, with more
+subsystems and drivers being written in Rust alongside traditional C code.
+In the near future, practically useful drivers and subsystems for Armbian users
+are expected to require or benefit from Rust kernel support. Enabling
+`CONFIG_RUST` in the kernel build unlocks this capability.
+
+Without this extension, Armbian kernels are built without Rust support —
+the toolchain is not installed and `CONFIG_RUST` does not appear in
+menuconfig. This extension installs a pinned Rust toolchain via `rustup`,
+enables `CONFIG_RUST` automatically, and configures all required build
+parameters so that Rust kernel modules can be compiled alongside C code.
+The toolchain versions and other aspects of the build can be adjusted via
+[parameters](#parameters) passed to the build system.
+
+## Why rustup instead of distro packages
+
+Distribution-provided Rust packages currently cannot fully satisfy all the
+requirements for enabling Rust in a recent kernel. Mixing some components
+from the distro with others from external sources is fragile and not
+worthwhile. For this reason the extension downloads a complete, version-pinned
+toolchain via `rustup` independently of the host distro.
+
+When the base distro used by the Armbian build system provides packages
+sufficient to build the Rust environment for the latest kernels entirely from
+distro sources, Armbian will likely switch to using them.
+
+## Quick start
+
+```bash
+./compile.sh BOARD=<board> BRANCH=<branch> ENABLE_EXTENSIONS="kernel-rust"
+```
+
+To open menuconfig with Rust options visible:
+
+```bash
+./compile.sh kernel-config BOARD=<board> BRANCH=<branch> ENABLE_EXTENSIONS="kernel-rust"
+```
+
+To enable permanently from a userconfig file:
+
+```bash
+enable_extension "kernel-rust"
+```
+
+## Requirements
+
+- **Kernel version**: 6.12 or newer. The minimum required rustc version depends on the kernel release; see the [Rust-for-Linux version policy](https://rust-for-linux.com/rust-version-policy).
+- **Host package**: `libclang-dev` — installed automatically by the extension.
+- **Build host architecture**: x86_64, aarch64, or riscv64.
+- Internet access on first use (downloads rustup-init and toolchain components).
+
+## Parameters
+
+| Variable | Default | Description |
+|---|---|---|
+| **`RUST_VERSION`** | `1.85.0` | rustc version installed via rustup. |
+| **`BINDGEN_VERSION`** | `0.71.1` | `bindgen-cli` version installed via cargo. |
+| **`RUST_KERNEL_SAMPLES`** | `no` | Set to `yes` to build sample Rust kernel modules (`rust_minimal`, `rust_print`, `rust_driver_faux`) as loadable modules. Useful for smoke-testing the toolchain. |
+| **`RUST_EXTRA_COMPONENTS`** | _(empty array)_ | Additional rustup components to install (e.g. `clippy`, `llvm-tools`). |
+| **`RUST_EXTRA_CARGO_CRATES`** | _(empty array)_ | Additional cargo crates to install. Supports `name` or `name@version` syntax. |
+
+## Toolchain cache
+
+The toolchain is installed once into `${SRC}/cache/tools/rustup/` and reused
+across builds. The cache is content-addressed by a hash of:
+
+- `RUST_VERSION`
+- `BINDGEN_VERSION`
+- build host architecture
+- `RUST_EXTRA_COMPONENTS`
+- `RUST_EXTRA_CARGO_CRATES`
+
+Changing any of these values invalidates the cache and triggers a full reinstall
+on the next build. The marker file is `.marker-<hash>` inside the cache directory.
+
+## Extensibility
+
+Other extensions can request additional toolchain components or crates before
+the toolchain is installed:
+
+```bash
+# In your extension file:
+RUST_EXTRA_COMPONENTS+=("clippy" "llvm-tools")
+RUST_EXTRA_CARGO_CRATES+=("mdbook" "cargo-deb@2.11.0")
+```
+
+## Kernel artifact versioning
+
+The extension adds a short hash of `RUST_VERSION|BINDGEN_VERSION` to the kernel
+artifact version string (key `_R`, e.g. `rust1a2b`). This ensures that changing
+toolchain versions triggers a kernel rebuild even if the kernel source is
+unchanged.
+
+## Implementation notes
+
+### env -i isolation
+
+The kernel build runs under `env -i`, which clears the entire environment.
+The extension passes Rust tool paths directly as make parameters
+(`RUSTC=`, `RUSTFMT=`, `BINDGEN=`) and sets `RUST_LIB_SRC` via the make
+environment array. Direct paths into the toolchain sysroot are used instead
+of rustup proxy binaries, so `RUSTUP_HOME` does not need to be in the
+cleared environment.
+
+### ccache and Rust
+
+ccache does not support rustc (upstream won't-fix since 2019). The kernel
+build system has no `RUSTC_WRAPPER` mechanism, so Rust compilation is not
+cached by ccache. Only C/assembly compilation benefits from ccache when this
+extension is active.
+
+## References
+
+- [Rust in the Linux kernel — quick start](https://docs.kernel.org/rust/quick-start.html)
+- [Rust for Linux — version policy](https://rust-for-linux.com/rust-version-policy)
+- [rustup installation](https://rust-lang.github.io/rustup/installation/index.html)
diff --git a/docs/Developer-Guide_Extensions-List.md b/docs/Developer-Guide_Extensions-List.md
index d3d09bdb..f8cc1afe 100644
--- a/docs/Developer-Guide_Extensions-List.md
+++ b/docs/Developer-Guide_Extensions-List.md
@@ -222,6 +222,8 @@ Adds JetHub device flashing support to the build.
 
 Enables Rust language support in the Linux kernel (`CONFIG_RUST`). Installs a rustup-managed toolchain into `${SRC}/cache/tools/rustup/` and configures all required make parameters.
 
+See: [kernel-rust extension](Developer-Guide_Extension-kernel-rust.md)
+
 ---
 
 ## kernel-version-toolchain
diff --git a/mkdocs.yml b/mkdocs.yml
index 4a04269f..bafe9435 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -163,6 +163,7 @@ nav:
         - 'Building with Docker' : 'Developer-Guide_Building-with-Docker.md'
         - 'Extensions Framework' : 'Developer-Guide_Extensions.md'
         - 'Extensions List' : 'Developer-Guide_Extensions-List.md'
+        - 'Extension: kernel-rust' : 'Developer-Guide_Extension-kernel-rust.md'
 
   - 'ARMBIAN COMMUNITY' :
         - 'Forums' : 'Community_Forums.md'

From c3f6f0d8c997ca35dc0d107171eb9c2a5e3edc4c Mon Sep 17 00:00:00 2001
From: Igor Velkov <325961+iav@users.noreply.github.com>
Date: Fri, 6 Mar 2026 03:19:14 +0200
Subject: [PATCH 3/3] docs: add ccache-remote extension dedicated page

Add Developer-Guide_Extension-ccache-remote.md with full documentation:
overview with backend comparison (Redis vs WebDAV), auto-discovery via
Avahi vs explicit configuration, quick start, parameters with URL format,
server discovery priority, cache sharing requirements, and server setup
guides for Redis and HTTP/WebDAV.

Update Extensions List to link to the new page.
Add ccache-remote to mkdocs.yml navigation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 ...Developer-Guide_Extension-ccache-remote.md | 257 ++++++++++++++++++
 docs/Developer-Guide_Extensions-List.md       |   2 +
 mkdocs.yml                                    |   1 +
 3 files changed, 260 insertions(+)
 create mode 100644 docs/Developer-Guide_Extension-ccache-remote.md

diff --git a/docs/Developer-Guide_Extension-ccache-remote.md b/docs/Developer-Guide_Extension-ccache-remote.md
new file mode 100644
index 00000000..320558ab
--- /dev/null
+++ b/docs/Developer-Guide_Extension-ccache-remote.md
@@ -0,0 +1,257 @@
+# Extension: ccache-remote
+
+[ccache](https://ccache.dev/) significantly speeds up repeated kernel and
+U-Boot builds by caching compiled objects. By default, each build host has
+its own local cache. This extension adds a **shared remote cache** so that
+multiple build machines (or a CI server and a developer workstation) can all
+benefit from objects already compiled by someone else.
+
+Typical scenarios:
+
+- A home lab with several SBCs used as build hosts — first build populates
+  the cache, subsequent builds on other machines hit it.
+- A CI server and developer laptops sharing one cache server so that a
+  developer rarely needs to compile from scratch after CI has run.
+- A single machine where the local cache was lost (disk wiped) but the
+  remote cache is still warm.
+
+The extension supports two backends:
+
+- **Redis** — lower latency, recommended for fast local networks. Cache lives
+  entirely in RAM on the server, so capacity is limited by available memory.
+- **HTTP/WebDAV** (nginx) — somewhat slower, but stores cache on disk. Can
+  be orders of magnitude larger than a RAM-backed Redis instance, making it
+  a better choice when cache size matters more than speed.
+
+### Auto-discovery vs. explicit configuration
+
+The simplest deployment uses **Avahi (DNS-SD)**. Once the cache server is
+set up and publishing its service, and Avahi is installed on all build hosts,
+enabling the extension is all that is needed — no URL configuration required.
+
+If Avahi is not available or not desirable, the server URL must be provided
+explicitly via `CCACHE_REMOTE_STORAGE`, or for remote servers via
+`CCACHE_REMOTE_DOMAIN` (DNS SRV). See [Parameters](#parameters) below.
+
+The extension automatically enables `USE_CCACHE=yes` and handles all ccache
+configuration including Docker pass-through.
+
+## Quick start
+
+If a cache server is already running on the local network and advertising
+itself via DNS-SD (Avahi), no configuration is needed:
+
+```bash
+./compile.sh BOARD=<board> BRANCH=<branch> ENABLE_EXTENSIONS="ccache-remote"
+```
+
+With an explicit Redis server:
+
+```bash
+./compile.sh BOARD=<board> BRANCH=<branch> \
+  ENABLE_EXTENSIONS="ccache-remote" \
+  CCACHE_REMOTE_STORAGE="redis://192.168.1.65:6379"
+```
+
+With an explicit HTTP/WebDAV server:
+
+```bash
+./compile.sh BOARD=<board> BRANCH=<branch> \
+  ENABLE_EXTENSIONS="ccache-remote" \
+  CCACHE_REMOTE_STORAGE="http://192.168.1.65:8088/ccache/"
+```
+
+To enable permanently from a userconfig file:
+
+```bash
+enable_extension "ccache-remote"
+# optionally:
+# CCACHE_REMOTE_STORAGE="redis://192.168.1.65:6379"
+```
+
+## Requirements
+
+- **ccache**: version 4.4 or newer (for remote storage support).
+- **Redis backend**: Redis server accessible from the build host.
+- **HTTP backend**: nginx with WebDAV module (`nginx-extras`).
+- **Auto-discovery**: `avahi-browse` (package `avahi-utils`) on the build host.
+
+## Parameters
+
+| Variable | Default | Description |
+|---|---|---|
+| **`CCACHE_REMOTE_STORAGE`** | _(empty)_ | Remote storage URL. If not set, auto-discovery is attempted. |
+| **`CCACHE_REMOTE_DOMAIN`** | _(empty)_ | Domain for DNS SRV discovery (e.g. `example.com`). |
+| **`CCACHE_REMOTE_ONLY`** | `no` | Set to `yes` to disable local cache and use only remote storage (saves local disk space). |
+| **`CCACHE_REDIS_CONNECT_TIMEOUT`** | `500` | Redis connection timeout in milliseconds. |
+| **`CCACHE_READONLY`** | _(empty)_ | Set to any value to use cache read-only (don't write new entries). |
+| **`CCACHE_RECACHE`** | _(empty)_ | Recompile everything and update cache (bypass existing entries). |
+| **`CCACHE_RESHARE`** | _(empty)_ | Push existing local cache entries to remote storage. |
+| **`CCACHE_MAXSIZE`** | _(empty)_ | Maximum local cache size (e.g. `10G`). |
+| **`CCACHE_NAMESPACE`** | _(empty)_ | Namespace for cache isolation between projects or branches. |
+| **`CCACHE_DISABLE`** | _(empty)_ | Set to any value to disable ccache completely. |
+
+For the full list of supported variables see the `CCACHE_PASSTHROUGH_VARS`
+array in the extension source or the
+[ccache configuration reference](https://ccache.dev/manual/latest.html#config_remote_storage).
+
+### CCACHE_REMOTE_STORAGE URL format
+
+```
+Redis:  redis://[[USER:]PASSWORD@]HOST[:PORT][|attribute=value...]
+HTTP:   http://HOST[:PORT]/PATH/[|attribute=value...]
+```
+
+Common attributes:
+
+| Attribute | Default | Description |
+|---|---|---|
+| `connect-timeout` | `100` ms | Connection timeout. Increase on slow networks. |
+| `operation-timeout` | `10000` ms | Per-operation timeout. |
+
+Examples:
+
+```
+redis://192.168.1.65:6379|connect-timeout=500
+redis://default:secretpass@192.168.1.65:6379|connect-timeout=500
+http://192.168.1.65:8088/ccache/
+```
+
+!!! warning
+    Redis passwords must not contain `/`, `+`, `=`, or spaces — these break
+    URL parsing. Generate a safe password with:
+    ```bash
+    openssl rand -hex 24
+    ```
+
+## Server discovery
+
+When `CCACHE_REMOTE_STORAGE` is not set, the extension tries to discover a
+cache server automatically in this order:
+
+1. **DNS-SD** (mDNS / Avahi): browse for `_ccache._tcp` on the local network.
+   Requires `avahi-browse` on the build host and the cache server publishing
+   a DNS-SD service. Redis is preferred over HTTP when both are found.
+
+2. **DNS SRV**: query `_ccache._tcp.DOMAIN` when `CCACHE_REMOTE_DOMAIN` is
+   set. Useful for remote or cloud-hosted build servers.
+
+3. **Legacy mDNS**: resolve the hostname `ccache.local` (falls back to Redis
+   on port 6379). Kept for backward compatibility.
+
+If none of these succeeds, the extension silently falls back to local cache only.
+
+## Cache sharing requirements
+
+For the cache to be shared across multiple build hosts, **the Armbian source
+tree must be at the same path on all machines** (e.g. `/home/build/armbian`).
+ccache includes the working directory in the cache key, so different paths
+produce different keys and the cache will not be shared.
+
+Docker builds are not affected — they always use a consistent internal path.
+
+## Server setup
+
+### Redis (recommended)
+
+1. Install:
+
+    ```bash
+    apt install redis-server avahi-daemon avahi-utils
+    ```
+
+2. Configure Redis — copy `misc/redis/redis-ccache.conf` from the extension
+   directory and include it in `/etc/redis/redis.conf`:
+
+    ```bash
+    echo "include /etc/redis/redis-ccache.conf" >> /etc/redis/redis.conf
+    systemctl restart redis-server
+    ```
+
+3. Set a password (recommended for any non-isolated network):
+
+    ```bash
+    openssl rand -hex 24   # use output as password
+    # set requirepass <password> in redis-ccache.conf
+    ```
+
+4. Publish the DNS-SD service so clients discover it automatically:
+
+    ```bash
+    # Static (always advertise):
+    cp misc/avahi/ccache-redis.service /etc/avahi/services/
+
+    # Or tied to redis-server lifecycle:
+    cp misc/systemd/ccache-avahi-redis.service /etc/systemd/system/
+    systemctl enable --now ccache-avahi-redis
+    ```
+
+### HTTP/WebDAV (nginx)
+
+1. Install:
+
+    ```bash
+    apt install nginx-extras avahi-daemon avahi-utils
+    ```
+
+2. Enable the WebDAV site:
+
+    ```bash
+    cp misc/nginx/ccache-webdav.conf /etc/nginx/sites-available/ccache-webdav
+    ln -s /etc/nginx/sites-available/ccache-webdav /etc/nginx/sites-enabled/
+    mkdir -p /var/cache/ccache-webdav/ccache
+    chown -R www-data:www-data /var/cache/ccache-webdav
+    systemctl reload nginx
+    ```
+
+3. Verify:
+
+    ```bash
+    curl -X PUT -d "test" http://localhost:8088/ccache/test.txt
+    curl http://localhost:8088/ccache/test.txt
+    ```
+
+    !!! warning
+        The provided nginx configuration has no authentication. Use only on a
+        trusted private network.
+
+4. Publish the DNS-SD service:
+
+    ```bash
+    cp misc/avahi/ccache-webdav.service /etc/avahi/services/
+    ```
+
+### DNS SRV records (remote servers)
+
+For build hosts that cannot reach the cache server via mDNS, set
+`CCACHE_REMOTE_DOMAIN` and create DNS records:
+
+Redis backend:
+```text
+_ccache._tcp.example.com.  SRV  0 0 6379 ccache.example.com.
+_ccache._tcp.example.com.  TXT  "type=redis"
+```
+
+HTTP/WebDAV backend:
+```text
+_ccache._tcp.example.com.  SRV  0 0 8088 ccache.example.com.
+_ccache._tcp.example.com.  TXT  "type=http" "path=/ccache/"
+```
+
+### mDNS client requirements
+
+For `.local` hostname resolution to work on the build host:
+
+```bash
+# Option A: systemd-resolved
+apt install libnss-resolve
+
+# Option B: standalone
+apt install libnss-mdns
+```
+
+## References
+
+- [ccache remote storage documentation](https://ccache.dev/manual/latest.html#config_remote_storage)
+- [ccache Redis how-to](https://ccache.dev/howto/redis-storage.html)
+- [ccache HTTP how-to](https://ccache.dev/howto/http-storage.html)
diff --git a/docs/Developer-Guide_Extensions-List.md b/docs/Developer-Guide_Extensions-List.md
index f8cc1afe..26de5278 100644
--- a/docs/Developer-Guide_Extensions-List.md
+++ b/docs/Developer-Guide_Extensions-List.md
@@ -78,6 +78,8 @@ Adds a C++ compiler to host build dependencies. The C++ compiler is no longer in
 
 Enables ccache with a remote storage backend (Redis or HTTP/WebDAV) for sharing the compilation cache across multiple build hosts. Requires ccache 4.4+.
 
+See: [ccache-remote extension](Developer-Guide_Extension-ccache-remote.md)
+
 ---
 
 ## cleanup-space-final-image
diff --git a/mkdocs.yml b/mkdocs.yml
index bafe9435..42a6e2a5 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -164,6 +164,7 @@ nav:
         - 'Extensions Framework' : 'Developer-Guide_Extensions.md'
         - 'Extensions List' : 'Developer-Guide_Extensions-List.md'
         - 'Extension: kernel-rust' : 'Developer-Guide_Extension-kernel-rust.md'
+        - 'Extension: ccache-remote' : 'Developer-Guide_Extension-ccache-remote.md'
 
   - 'ARMBIAN COMMUNITY' :
         - 'Forums' : 'Community_Forums.md'