Add building instructions and prebuilt kernel info to README.md

README.md

@@ -9,7 +9,41 @@ Use this repository to compile TWRP from source.
 
 This device tree should also work for Acer Iconia B1-710 and Lenovo IdeaTab A1000 with either minor or no changes at all.
 
-## Notes
+## Building
 
-Prebuilt kernel binary used here is built from this source code: https://github.com/arzam16/mt6577_kernel_Acer_B1_A71
+Tools needed: `repo` and some cross-compiling toolchain. Linaro v7.5.0 works great.
 
+**1. Get the TWRP source code**
+
+`repo init -u https://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni -b twrp-4.4 --depth 1`
+
+If this command fails due to some unspecified credentials error, you can bypass it by executing:
+
+`cd .repo/manifests && git config user.name 'test' && git config user.email 'test@ema.il' && cd ../..`
+
+and then running `repo init` thing from above again.
+
+**2. Get the device tree**
+
+```
+mkdir -p device/acer/giordano
+git clone https://github.com/arzam16/android_device_acer_giordano device/acer/giordano
+```
+
+**3. Build it!**
+
+```
+. build/envsetup.sh
+lunch omni_giordano-userdebug
+make recoveryimage
+```
+
+Feel free to specify `-jTHREADS` option in `make` command to speed up compilation. `lunch` command yields some dependency warning, but it still builds fine. The recovery image for flashing will be located at `out/target/product/giordano/recovery.img`
+
+## Notes on kernel
+
+This device tree uses prebuilt kernel which could be easily reproduced:
+
+* Source code: https://github.com/arzam16/mt6577_kernel_Acer_B1_A71
+* Commit: `67a47ce448ed2dad6004f1d5244d5fc26a0907ef`
+* Config: `prebuilt/kernel.config`