diff --git a/devices/flash-imxrt/Makefile b/devices/flash-imxrt/Makefile
index fe9a8fe1..6fd8f26c 100644
--- a/devices/flash-imxrt/Makefile
+++ b/devices/flash-imxrt/Makefile
@@ -9,11 +9,11 @@
 FLEXSPI_OBJS := fspi/fspi.o
 
 ifneq (, $(findstring imxrt117x, $(TARGET_SUBFAMILY)))
-  FLEXSPI_OBJS += flashdrv.o nor/nor.o nor/nor_mx.o
+  FLEXSPI_OBJS += flashdrv.o nor/nor.o nor/nor_mx.o nor/nor_issi.o
 else ifneq (, $(findstring imxrt106x, $(TARGET_SUBFAMILY)))
-  FLEXSPI_OBJS += flashdrv.o nor/nor.o nor/nor_mx.o
+  FLEXSPI_OBJS += flashdrv.o nor/nor.o nor/nor_mx.o nor/nor_issi.o
 else ifneq (, $(findstring imxrt105x, $(TARGET_SUBFAMILY)))
-  FLEXSPI_OBJS += flashdrv.o nor/nor.o nor/nor_mx.o hyperbus/hyper.o
+  FLEXSPI_OBJS += flashdrv.o nor/nor.o nor/nor_mx.o nor/nor_issi.o hyperbus/hyper.o
 endif
 
 OBJS += $(addprefix $(PREFIX_O)devices/flash-imxrt/, $(FLEXSPI_OBJS))
diff --git a/devices/flash-imxrt/flashdrv.c b/devices/flash-imxrt/flashdrv.c
index 399740db..dd4ef30e 100644
--- a/devices/flash-imxrt/flashdrv.c
+++ b/devices/flash-imxrt/flashdrv.c
@@ -443,6 +443,8 @@ static int flashdrv_init(unsigned int minor)
 		flashSz[port] = dev->nor->totalSz;
 		flexspi_setFlashSize(&dev->fspi, flashSz, FLEXSPI_PORTS);
 
+		flexspi_postinit(&dev->fspi);
+
 		lib_printf("\ndev/flash/nor: Configured %s %s %dMB nor flash(%d.%d)",
 			vendor, dev->nor->name, dev->nor->totalSz >> 20, DEV_STORAGE, minor);
 
diff --git a/devices/flash-imxrt/fspi.h b/devices/flash-imxrt/fspi.h
index 2950278c..eeb10463 100644
--- a/devices/flash-imxrt/fspi.h
+++ b/devices/flash-imxrt/fspi.h
@@ -82,6 +82,10 @@ struct xferOp {
 extern int flexspi_init(flexspi_t *fspi, int instance, u8 slPortMask);
 
 
+/* Post-initialize single FlexSPI module */
+extern int flexspi_postinit(flexspi_t *fspi);
+
+
 /* Safely deinit leaving XIP working */
 extern int flexspi_deinit(flexspi_t *fspi);
 
diff --git a/devices/flash-imxrt/fspi/fspi.c b/devices/flash-imxrt/fspi/fspi.c
index 449048bf..d65955c0 100644
--- a/devices/flash-imxrt/fspi/fspi.c
+++ b/devices/flash-imxrt/fspi/fspi.c
@@ -139,7 +139,8 @@ __attribute__((section(".noxip"))) int flexspi_init(flexspi_t *fspi, int instanc
 	hal_invalDCacheAll();
 	hal_cleanDCache();
 
-	flexspi_clockConfig(fspi);
+	/* Configure clock for normal read */
+	flexspi_clockConfig(fspi, 0);
 
 	/* Release FlexSPI from reset and power SRAM */
 	flexspi_disable(fspi, 0);
@@ -212,10 +213,10 @@ __attribute__((section(".noxip"))) int flexspi_init(flexspi_t *fspi, int instanc
 	/* Enable FlexSPI before updating LUT */
 	flexspi_disable(fspi, 0);
 
-	/* Default fast (up to 133MHz) read (single pad) used by AHB and XIP */
-	lut[0] = LUT_SEQ(lutCmd_SDR, lutPad1, 0x0b, lutCmdRADDR_SDR, lutPad1, 0x18);
-	lut[1] = LUT_SEQ(lutCmdDUMMY_SDR, lutPad1, 0x08, lutCmdREAD_SDR, lutPad1, 0x04);
-	lut[2] = LUT_SEQ(lutCmdSTOP, lutPad1, 0, 0, 0, 0);
+	/* Default normal (up to 80 MHz) read (single pad) used by AHB and XIP */
+	lut[0] = LUT_SEQ(lutCmd_SDR, lutPad1, 0x03, lutCmdRADDR_SDR, lutPad1, 0x18);
+	lut[1] = LUT_SEQ(lutCmdREAD_SDR, lutPad1, 0x04, lutCmdSTOP, lutPad1, 0);
+	lut[2] = 0;
 	lut[3] = 0;
 
 	/* Configure initial LUT sequences as needed (for AHB read and IP) */
@@ -233,6 +234,15 @@ __attribute__((section(".noxip"))) int flexspi_init(flexspi_t *fspi, int instanc
 }
 
 
+__attribute__((section(".noxip"))) int flexspi_postinit(flexspi_t *fspi)
+{
+	/* Reconfigure clock for fast read */
+	flexspi_clockConfig(fspi, 1);
+
+	return EOK;
+}
+
+
 void flexspi_setFlashSize(flexspi_t *fspi, const size_t *flashSizes, size_t count)
 {
 	unsigned int i;
diff --git a/devices/flash-imxrt/fspi/fspi_rt105x.h b/devices/flash-imxrt/fspi/fspi_rt105x.h
index ff059a76..f2160b3a 100644
--- a/devices/flash-imxrt/fspi/fspi_rt105x.h
+++ b/devices/flash-imxrt/fspi/fspi_rt105x.h
@@ -41,12 +41,12 @@ static inline void *flexspi_getBase(int instance)
 }
 
 
-__attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fspi)
+__attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fspi, u8 fast)
 {
 	_imxrt_ccmControlGate(pctl_clk_flexspi, clk_state_off);
-	_imxrt_ccmSetDiv(clk_div_flexspi, 1); /* div2 -> 130 MHz */
-	_imxrt_ccmSetMux(clk_mux_flexspi, 3); /* PLL3 PFD0 */
-	_imxrt_ccmInitUsb1Pfd(clk_pfd0, 33);  /* PLL3_PDF0=261.818MHz */
+	_imxrt_ccmSetDiv(clk_div_flexspi, fast ? 1 : 3); /* Fast: 261 / (1 + 1) => 130 MHz, Normal: 261 / (3 + 1) => 65 MHz */
+	_imxrt_ccmSetMux(clk_mux_flexspi, 3);            /* PLL3 PFD0 */
+	_imxrt_ccmInitUsb1Pfd(clk_pfd0, 33);             /* PLL3_PDF0=261.818MHz */
 	_imxrt_ccmControlGate(pctl_clk_flexspi, clk_state_run_wait);
 }
 
diff --git a/devices/flash-imxrt/fspi/fspi_rt106x.h b/devices/flash-imxrt/fspi/fspi_rt106x.h
index d1a8d599..3b9ba1ca 100644
--- a/devices/flash-imxrt/fspi/fspi_rt106x.h
+++ b/devices/flash-imxrt/fspi/fspi_rt106x.h
@@ -50,20 +50,20 @@ static void *flexspi_getBase(int instance)
 }
 
 
-__attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fspi)
+__attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fspi, u8 fast)
 {
 	if (fspi->instance == flexspi_instance1) {
 		_imxrt_ccmControlGate(pctl_clk_flexspi, clk_state_off);
-		_imxrt_ccmInitUsb1Pfd(clk_pfd0, 13);  /* PLL3_PDF0=664.6MHz */
-		_imxrt_ccmSetDiv(clk_div_flexspi, 4); /* div5 */
-		_imxrt_ccmSetMux(clk_mux_flexspi, 3); /* PLL3 PFD0 */
+		_imxrt_ccmInitUsb1Pfd(clk_pfd0, 13);             /* PLL3_PDF0=664.6MHz */
+		_imxrt_ccmSetDiv(clk_div_flexspi, fast ? 4 : 9); /* Fast: 664 / (4 + 1) => 132 MHz, Normal: 664 / (9 + 1) => 66 MHz */
+		_imxrt_ccmSetMux(clk_mux_flexspi, 3);            /* PLL3 PFD0 */
 		_imxrt_ccmControlGate(pctl_clk_flexspi, clk_state_run_wait);
 	}
 	else if (fspi->instance == flexspi_instance2) {
 		_imxrt_ccmControlGate(pctl_clk_flexspi2, clk_state_off);
-		_imxrt_ccmInitUsb1Pfd(clk_pfd0, 13);   /* PLL3_PDF0=664.6MHz */
-		_imxrt_ccmSetDiv(clk_div_flexspi2, 4); /* div5 */
-		_imxrt_ccmSetMux(clk_mux_flexspi2, 1); /* PLL3 PFD0 */
+		_imxrt_ccmInitUsb1Pfd(clk_pfd0, 13);              /* PLL3_PDF0=664.6MHz */
+		_imxrt_ccmSetDiv(clk_div_flexspi2, fast ? 4 : 9); /* Fast: 664 / (4 + 1) => 132 MHz, Normal: 664 / (9 + 1) => 66 MHz */
+		_imxrt_ccmSetMux(clk_mux_flexspi2, 1);            /* PLL3 PFD0 */
 		_imxrt_ccmControlGate(pctl_clk_flexspi2, clk_state_run_wait);
 	}
 }
diff --git a/devices/flash-imxrt/fspi/fspi_rt117x.h b/devices/flash-imxrt/fspi/fspi_rt117x.h
index 9f72dce7..0df20f5b 100644
--- a/devices/flash-imxrt/fspi/fspi_rt117x.h
+++ b/devices/flash-imxrt/fspi/fspi_rt117x.h
@@ -53,7 +53,7 @@ static void *flexspi_getBase(int instance)
 }
 
 
-__attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fspi)
+__attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fspi, u8 fast)
 {
 	int gate, clk, div, mux, mfd, mfn;
 
@@ -61,7 +61,7 @@ __attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fs
 		case flexspi_instance1:
 			clk = pctl_clk_flexspi1;
 			gate = pctl_lpcg_flexspi1;
-			div = 3;                               /* SYS_PLL2_CLK / (3 + 1) => 132 MHz */
+			div = fast ? 3 : 7;                    /* Fast: 528 / (3 + 1) => 132 MHz, Normal: 528 / (7 + 1) => 66 MHz */
 			mux = mux_clkroot_flexspi1_syspll2out; /* Select main clock: SYS_PLL2_CLK = 528 MHz */
 			mfd = 0;
 			mfn = 0;
@@ -70,8 +70,8 @@ __attribute__((section(".noxip"))) static void flexspi_clockConfig(flexspi_t *fs
 		case flexspi_instance2:
 			clk = pctl_clk_flexspi2;
 			gate = pctl_lpcg_flexspi2;
-			div = 3;                               /* SYS_PLL2_CLK / (3 + 1) => 132 MHz */
-			mux = mux_clkroot_flexspi2_syspll2out; /* Select main clock: SYS_PLL2_CLK = 528 MHz */
+			div = fast ? 3 : 7;                    /* Fast: 528 / (3 + 1) => 132 MHz, Normal: 528 / (7 + 1) => 66 MHz */
+			mux = mux_clkroot_flexspi1_syspll2out; /* Select main clock: SYS_PLL2_CLK = 528 MHz */
 			mfd = 0;
 			mfn = 0;
 			break;
diff --git a/devices/flash-imxrt/nor/flash.h b/devices/flash-imxrt/nor/flash.h
index f0e59044..b0b51d38 100644
--- a/devices/flash-imxrt/nor/flash.h
+++ b/devices/flash-imxrt/nor/flash.h
@@ -66,6 +66,8 @@
 #define FLASH_CMD_ERRS       0x7a /* Program/erase resume */
 #define FLASH_CMD_EN4B       0xb7 /* Enter 4-byte address mode */
 #define FLASH_CMD_EX4B       0xe9 /* Exit 4-byte address mode */
+#define FLASH_CMD_RDRD       0x61 /* ISSI: Read Read Parameters (volatile) */
+#define FLASH_CMD_SRPV       0x63 /* ISSI: Set Read Parameters (volatile) */
 
 
 #endif /* _FLASH_H_ */
diff --git a/devices/flash-imxrt/nor/nor.c b/devices/flash-imxrt/nor/nor.c
index 4162289a..cae62cfa 100644
--- a/devices/flash-imxrt/nor/nor.c
+++ b/devices/flash-imxrt/nor/nor.c
@@ -47,11 +47,11 @@ static const struct nor_info flashInfo[] = {
 	{ FLASH_ID(0xef, 0x8019), "W25Q256JW-M", 32 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutGeneric4Byte, NULL },
 
 	/* ISSI */
-	{ FLASH_ID(0x9d, 0x7016), "IS25WP032", 4 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutGeneric3Byte, NULL },
-	{ FLASH_ID(0x9d, 0x7017), "IS25WP064", 8 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutGeneric3Byte, NULL },
-	{ FLASH_ID(0x9d, 0x7018), "IS25WP128", 16 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutGeneric3Byte, NULL },
-	{ FLASH_ID(0x9d, 0x7019), "IS25WP256", 32 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutGeneric4Byte, nor_mxQuadEnable },
-	{ FLASH_ID(0x9d, 0x6019), "IS25LP256", 32 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutGeneric4Byte, nor_mxQuadEnable },
+	{ FLASH_ID(0x9d, 0x7016), "IS25WP032", 4 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutIssi3Byte, nor_issiInit },
+	{ FLASH_ID(0x9d, 0x7017), "IS25WP064", 8 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutIssi3Byte, nor_issiInit },
+	{ FLASH_ID(0x9d, 0x7018), "IS25WP128", 16 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutIssi3Byte, nor_issiInit },
+	{ FLASH_ID(0x9d, 0x7019), "IS25WP256", 32 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutIssi4Byte, nor_issiInit },
+	{ FLASH_ID(0x9d, 0x6019), "IS25LP256", 32 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC, lutIssi4Byte, nor_issiInit },
 
 	/* Micron */
 	{ FLASH_ID(0x20, 0xba19), "MT25QL256", 32 * 1024 * 1024, 0x100, 0x1000, NOR_CAPS_GENERIC | NOR_CAPS_EN4B, lutMicronMono, NULL },
diff --git a/devices/flash-imxrt/nor/nor.h b/devices/flash-imxrt/nor/nor.h
index 4884bc91..6794788c 100644
--- a/devices/flash-imxrt/nor/nor.h
+++ b/devices/flash-imxrt/nor/nor.h
@@ -92,4 +92,8 @@ extern int nor_probe(flexspi_t *fspi, u8 port, const struct nor_info **pInfo, co
 int nor_mxQuadEnable(struct nor_device *dev);
 
 
+/* ISSI chip init */
+int nor_issiInit(struct nor_device *dev);
+
+
 #endif /* _FLEXSPI_NOR_H_ */
diff --git a/devices/flash-imxrt/nor/nor_issi.c b/devices/flash-imxrt/nor/nor_issi.c
new file mode 100644
index 00000000..f535f5b8
--- /dev/null
+++ b/devices/flash-imxrt/nor/nor_issi.c
@@ -0,0 +1,118 @@
+/*
+ * Phoenix-RTOS
+ *
+ * Operating system loader
+ *
+ * i.MX RT nor flash device driver
+ * ISSI Specific
+ *
+ * Copyright 2024 Phoenix Systems
+ * Authors: Ziemowit Leszczynski
+ *
+ * This file is part of Phoenix-RTOS.
+ *
+ * %LICENSE%
+ */
+
+
+#include <lib/lib.h>
+#include <devices/devs.h>
+#include "../fspi.h"
+#include "../lut.h"
+
+#include "flash.h"
+#include "nor.h"
+
+
+int nor_issiInit(struct nor_device *dev)
+{
+	int res;
+	struct xferOp xfer;
+	u8 status, params;
+	const time_t timeout = 1000;
+
+	if (dev->active == 0) {
+		return -ENODEV;
+	}
+
+	/* Load only the necessary commands to enable quad mode and set dummy cycles. */
+	flexspi_lutUpdateEntries(&dev->fspi, fspi_readStatus * LUT_SEQSZ, dev->nor->lut + fspi_readStatus, 1, LUT_SEQSZ);
+	flexspi_lutUpdateEntries(&dev->fspi, fspi_writeStatus * LUT_SEQSZ, dev->nor->lut + fspi_writeStatus, 1, LUT_SEQSZ);
+	flexspi_lutUpdateEntries(&dev->fspi, fspi_writeEnable * LUT_SEQSZ, dev->nor->lut + fspi_writeEnable, 1, LUT_SEQSZ);
+	flexspi_lutUpdateEntries(&dev->fspi, fspi_cmdCustom1 * LUT_SEQSZ, dev->nor->lut + fspi_cmdCustom1, 1, LUT_SEQSZ);
+	flexspi_lutUpdateEntries(&dev->fspi, fspi_cmdCustom2 * LUT_SEQSZ, dev->nor->lut + fspi_cmdCustom2, 1, LUT_SEQSZ);
+
+	res = nor_readStatus(&dev->fspi, dev->port, &status, timeout);
+	if (res < EOK) {
+		return res;
+	}
+
+	if ((status & (1uL << 6u)) == 0uL) {
+		res = nor_writeEnable(&dev->fspi, dev->port, 1, timeout);
+		if (res < EOK) {
+			return res;
+		}
+
+		/* Quad Enable */
+		status |= (1uL << 6u);
+
+		xfer.op = xfer_opWrite;
+		xfer.port = dev->port;
+		xfer.timeout = timeout;
+		xfer.addr = 0;
+		xfer.seqIdx = LUT_SEQIDX(fspi_writeStatus);
+		xfer.seqNum = LUT_SEQNUM(fspi_writeStatus);
+		xfer.data.write.ptr = &status;
+		xfer.data.write.sz = 1;
+
+		res = flexspi_xferExec(&dev->fspi, &xfer);
+		if (res < EOK) {
+			return res;
+		}
+
+		res = nor_waitBusy(&dev->fspi, dev->port, timeout);
+		if (res < EOK) {
+			return res;
+		}
+	}
+
+	xfer.op = xfer_opRead;
+	xfer.port = dev->port;
+	xfer.timeout = timeout;
+	xfer.addr = 0;
+	xfer.seqIdx = LUT_SEQIDX(fspi_cmdCustom1);
+	xfer.seqNum = LUT_SEQNUM(fspi_cmdCustom1);
+	xfer.data.read.ptr = &params;
+	xfer.data.read.sz = 1;
+
+	res = flexspi_xferExec(&dev->fspi, &xfer);
+	if (res < EOK) {
+		return res;
+	}
+
+	if (((params & 0x87) >> 3u) != 11) {
+		/* 11 dummy cycles */
+		params = (params & 0x87) | (11uL << 3u);
+
+		xfer.op = xfer_opWrite;
+		xfer.port = dev->port;
+		xfer.timeout = timeout;
+		xfer.addr = 0;
+		xfer.seqIdx = LUT_SEQIDX(fspi_cmdCustom2);
+		xfer.seqNum = LUT_SEQNUM(fspi_cmdCustom2);
+		xfer.data.read.ptr = &params;
+		xfer.data.write.sz = 1;
+
+		res = flexspi_xferExec(&dev->fspi, &xfer);
+		if (res < EOK) {
+			return res;
+		}
+
+		res = nor_waitBusy(&dev->fspi, dev->port, timeout);
+		if (res < EOK) {
+			return res;
+		}
+	}
+
+	return EOK;
+}
diff --git a/devices/flash-imxrt/nor/nor_lut.h b/devices/flash-imxrt/nor/nor_lut.h
index d96501f5..90daafd1 100644
--- a/devices/flash-imxrt/nor/nor_lut.h
+++ b/devices/flash-imxrt/nor/nor_lut.h
@@ -181,7 +181,42 @@ static const u32 seq_micronExit4Byte[NOR_LUTSEQSZ] = {
 };
 
 
-/* Generic chips: ISSI, Winbond, Macronix (3-byte address) */
+/*
+ * ISSI NOR dedicated Command Sequences
+ */
+
+/* Read Fast Quad (3-byte address) for 133 MHz and 11 dummy cycles */
+static const u32 seq_issiReadData3Byte[NOR_LUTSEQSZ] = {
+	LUT_SEQ(lutCmd_SDR, lutPad1, FLASH_CMD_QIOR, lutCmdRADDR_SDR, lutPad4, 0x18),
+	LUT_SEQ(lutCmdMODE8_SDR, lutPad4, 0x00, lutCmdDUMMY_SDR, lutPad4, 0x09),
+	LUT_SEQ(lutCmdREAD_SDR, lutPad4, 0x04, lutCmdSTOP, lutPad1, 0),
+	0
+};
+
+/* Read Fast Quad (4-byte address) for 133 MHz and 11 dummy cycles */
+static const u32 seq_issiReadData4Byte[NOR_LUTSEQSZ] = {
+	LUT_SEQ(lutCmd_SDR, lutPad1, FLASH_CMD_4QIOR, lutCmdRADDR_SDR, lutPad4, 0x20),
+	LUT_SEQ(lutCmdMODE8_SDR, lutPad4, 0x00, lutCmdDUMMY_SDR, lutPad4, 0x09),
+	LUT_SEQ(lutCmdREAD_SDR, lutPad4, 0x04, lutCmdSTOP, lutPad1, 0),
+	0
+};
+
+/* Read Read Parameters */
+static const u32 seq_issiReadReadParameters[NOR_LUTSEQSZ] = {
+	LUT_SEQ(lutCmd_SDR, lutPad1, FLASH_CMD_RDRD, lutCmdREAD_SDR, lutPad1, 0x01),
+	LUT_SEQ(lutCmdSTOP, lutPad1, 0, 0, 0, 0),
+	0, 0
+};
+
+/* Write Read Parameters */
+static const u32 seq_issiWriteReadParameters[NOR_LUTSEQSZ] = {
+	LUT_SEQ(lutCmd_SDR, lutPad1, FLASH_CMD_SRPV, lutCmdWRITE_SDR, lutPad1, 0x01),
+	LUT_SEQ(lutCmdSTOP, lutPad1, 0, 0, 0, 0),
+	0, 0
+};
+
+
+/* Generic chips: Winbond, Macronix (3-byte address) */
 static const u32 *lutGeneric3Byte[LUT_ENTRIES] = {
 	[fspi_readData] = seq_genericReadData3Byte,
 	[fspi_readStatus] = seq_genericReadStatus,
@@ -195,7 +230,7 @@ static const u32 *lutGeneric3Byte[LUT_ENTRIES] = {
 	[fspi_readID] = seq_genericReadID,
 };
 
-/* Generic chips: ISSI, Winbond, Macronix (4-byte address) */
+/* Generic chips: Winbond, Macronix (4-byte address) */
 static const u32 *lutGeneric4Byte[LUT_ENTRIES] = {
 	[fspi_readData] = seq_genericReadData4Byte,
 	[fspi_readStatus] = seq_genericReadStatus,
@@ -239,4 +274,36 @@ static const u32 *lutMicronDie[LUT_ENTRIES] = {
 	[fspi_exit4byteAddr] = seq_micronExit4Byte,
 };
 
+/* ISSI chips (3-byte address) */
+static const u32 *lutIssi3Byte[LUT_ENTRIES] = {
+	[fspi_readData] = seq_issiReadData3Byte,
+	[fspi_readStatus] = seq_genericReadStatus,
+	[fspi_writeStatus] = seq_genericWriteStatus,
+	[fspi_writeEnable] = seq_genericWriteEnable,
+	[fspi_writeDisable] = seq_genericWriteDisable,
+	[fspi_eraseSector] = seq_genericEraseSector3Byte,
+	[fspi_eraseBlock] = seq_genericEraseBlock3Byte,
+	[fspi_eraseChip] = seq_genericEraseChip,
+	[fspi_programQPP] = seq_genericProgramQPP3Byte,
+	[fspi_readID] = seq_genericReadID,
+	[fspi_cmdCustom1] = seq_issiReadReadParameters,
+	[fspi_cmdCustom2] = seq_issiWriteReadParameters,
+};
+
+/* ISSI chips (4-byte address) */
+static const u32 *lutIssi4Byte[LUT_ENTRIES] = {
+	[fspi_readData] = seq_issiReadData4Byte,
+	[fspi_readStatus] = seq_genericReadStatus,
+	[fspi_writeStatus] = seq_genericWriteStatus,
+	[fspi_writeEnable] = seq_genericWriteEnable,
+	[fspi_writeDisable] = seq_genericWriteDisable,
+	[fspi_eraseSector] = seq_genericEraseSector4Byte,
+	[fspi_eraseBlock] = seq_genericEraseBlock4Byte,
+	[fspi_eraseChip] = seq_genericEraseChip,
+	[fspi_programQPP] = seq_genericProgramQPP4Byte,
+	[fspi_readID] = seq_genericReadID,
+	[fspi_cmdCustom1] = seq_issiReadReadParameters,
+	[fspi_cmdCustom2] = seq_issiWriteReadParameters,
+};
+
 #endif /* _LUTTABLES_H_ */
diff --git a/hal/armv7m/imxrt/10xx/105x/_init.S b/hal/armv7m/imxrt/10xx/105x/_init.S
index 7757f29b..9fc3e58f 100644
--- a/hal/armv7m/imxrt/10xx/105x/_init.S
+++ b/hal/armv7m/imxrt/10xx/105x/_init.S
@@ -52,7 +52,7 @@ _fcfb:
 .word 0x00000010 /* controllerMiscOption */
 .byte 0x1        /* deviceType */
 .byte 0x4        /* sflashPadType */
-.byte 0x8        /* serialClkFreq */
+.byte 0x3        /* serialClkFreq */
 .byte 0x0        /* lutCustomSeqEnable */
 .word 0, 0
 .word 0x800000   /* sflashA1Size */
@@ -70,7 +70,7 @@ _fcfb:
 .byte 0x0, 0     /* busyBitPolarity */
 
 /* lookupTable */
-.word 0x0818040b, 0x24043008, 0x00000000, 0x00000000
+.word 0x08180403, 0x00002404, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
diff --git a/hal/armv7m/imxrt/10xx/106x/_init.S b/hal/armv7m/imxrt/10xx/106x/_init.S
index 5917c17f..43190bad 100644
--- a/hal/armv7m/imxrt/10xx/106x/_init.S
+++ b/hal/armv7m/imxrt/10xx/106x/_init.S
@@ -52,7 +52,7 @@ _fcfb:
 .word 0x00000010 /* controllerMiscOption */
 .byte 0x1        /* deviceType */
 .byte 0x4        /* sflashPadType */
-.byte 0x8        /* serialClkFreq */
+.byte 0x3        /* serialClkFreq */
 .byte 0x0        /* lutCustomSeqEnable */
 .word 0, 0
 .word 0x800000   /* sflashA1Size */
@@ -70,7 +70,7 @@ _fcfb:
 .byte 0x0, 0     /* busyBitPolarity */
 
 /* lookupTable */
-.word 0x0818040b, 0x24043008, 0x00000000, 0x00000000
+.word 0x08180403, 0x00002404, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
diff --git a/hal/armv7m/imxrt/117x/_init.S b/hal/armv7m/imxrt/117x/_init.S
index 94e6fd96..2735b4e8 100644
--- a/hal/armv7m/imxrt/117x/_init.S
+++ b/hal/armv7m/imxrt/117x/_init.S
@@ -66,7 +66,7 @@ _fcfb:
 .word 0x00000010 /* controllerMiscOption */
 .byte 0x1        /* deviceType */
 .byte 0x4        /* sflashPadType */
-.byte 0x7        /* serialClkFreq */
+.byte 0x3        /* serialClkFreq */
 .byte 0x0        /* lutCustomSeqEnable */
 .word 0, 0
 .word 0x00010000 /* sflashA1Size */
@@ -85,7 +85,7 @@ _fcfb:
 
 /* lookupTable */
 
-.word 0x0818040b, 0x24043008, 0x00000000, 0x00000000
+.word 0x08180403, 0x00002404, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000
 .word 0x00000000, 0x00000000, 0x00000000, 0x00000000