diff --git a/boards/arm/stm32wl5/nucleo-wl55jc/Kconfig b/boards/arm/stm32wl5/nucleo-wl55jc/Kconfig
index 134d59c7aed..b22834bb01b 100644
--- a/boards/arm/stm32wl5/nucleo-wl55jc/Kconfig
+++ b/boards/arm/stm32wl5/nucleo-wl55jc/Kconfig
@@ -46,6 +46,19 @@ comment "FLASH partitioning and mounting requires !DISABLE_MOUNTPOINT"
 
 if ARCH_BOARD_FLASH_MOUNT
 
+config ARCH_BOARD_FLASH_BL_PROG_SIZE
+	int "Size reserved for bootloader program code"
+	default 0
+	---help---
+		How much memory to reserve for bootloader program code.
+		If you are using bootloader in your application, specify
+		max size of bootloader partition. This memory will be
+		reserved at the beginning of flash, and CPU1 progmem will
+		be right after bootloader.
+
+		If you don't use bootloader and just want to run program
+		directly after reset, set this to 0.
+
 config ARCH_BOARD_FLASH_CPU1_PROG_SIZE
 	int "Size reserved for CPU1 program code"
 	default 127
diff --git a/boards/arm/stm32wl5/nucleo-wl55jc/src/stm32_flash.c b/boards/arm/stm32wl5/nucleo-wl55jc/src/stm32_flash.c
index 1906580d35b..e9e7ed58913 100644
--- a/boards/arm/stm32wl5/nucleo-wl55jc/src/stm32_flash.c
+++ b/boards/arm/stm32wl5/nucleo-wl55jc/src/stm32_flash.c
@@ -41,6 +41,10 @@
 
 /* Define default values to silent compiler warning about undefined macro */
 
+#ifndef CONFIG_ARCH_BOARD_FLASH_BL_PROG_SIZE
+#define CONFIG_ARCH_BOARD_FLASH_BL_PROG_SIZE 0
+#endif
+
 #ifndef CONFIG_ARCH_BOARD_FLASH_CPU1_PROG_SIZE
 #define CONFIG_ARCH_BOARD_FLASH_CPU1_PROG_SIZE 0
 #endif
@@ -65,7 +69,8 @@
 #define CONFIG_ARCH_BOARD_FLASH_PART4_SIZE 0
 #endif
 
-#if (CONFIG_ARCH_BOARD_FLASH_CPU1_PROG_SIZE + \
+#if (CONFIG_ARCH_BOARD_FLASH_BL_PROG_SIZE + \
+     CONFIG_ARCH_BOARD_FLASH_CPU1_PROG_SIZE + \
      CONFIG_ARCH_BOARD_FLASH_CPU2_PROG_SIZE + \
      CONFIG_ARCH_BOARD_FLASH_PART1_SIZE + \
      CONFIG_ARCH_BOARD_FLASH_PART2_SIZE + \
@@ -74,7 +79,8 @@
 #   error "Sum of all flash pertitions cannot be bigger than 128"
 #endif
 
-#if (CONFIG_ARCH_BOARD_FLASH_CPU1_PROG_SIZE + \
+#if (CONFIG_ARCH_BOARD_FLASH_BL_PROG_SIZE + \
+     CONFIG_ARCH_BOARD_FLASH_CPU1_PROG_SIZE + \
      CONFIG_ARCH_BOARD_FLASH_CPU2_PROG_SIZE + \
      CONFIG_ARCH_BOARD_FLASH_PART1_SIZE + \
      CONFIG_ARCH_BOARD_FLASH_PART2_SIZE + \
@@ -101,6 +107,15 @@ struct part_table
 
 static const struct part_table part_table[] =
 {
+#if CONFIG_ARCH_BOARD_FLASH_BL_PROG_SIZE > 0
+  {
+    .size   = CONFIG_ARCH_BOARD_FLASH_BL_PROG_SIZE,
+    .name   = "bl-progmem",
+    .mnt    = NULL,
+    .fs     = "rawfs"
+  },
+#endif
+
   {
     .size   = CONFIG_ARCH_BOARD_FLASH_CPU1_PROG_SIZE,
     .name   = "cpu1-progmem",