diff --git a/records/board/thingy91.yaml b/records/board/thingy91.yaml
index 0a7d2c8478..68fc42d230 100644
--- a/records/board/thingy91.yaml
+++ b/records/board/thingy91.yaml
@@ -1,6 +1,8 @@
 common:
     macros:
+        - THINGY91
         - NRF_SECURE_BOOTLOADER
+        - NRF_SECURE_BOOTLOADER_OFFSET=0x12200
     sources:
         board:
             - source/board/thingy91.c
diff --git a/source/daplink/drag-n-drop/iap_flash_intf.c b/source/daplink/drag-n-drop/iap_flash_intf.c
index ca7b274cef..79903a17dd 100644
--- a/source/daplink/drag-n-drop/iap_flash_intf.c
+++ b/source/daplink/drag-n-drop/iap_flash_intf.c
@@ -30,6 +30,7 @@
 #include "crc.h"
 #include "info.h"
 
+#if !defined(DISABLE_FLASH_INTF_CHECKS)
 // Application start must be aligned to page write
 COMPILER_ASSERT(DAPLINK_ROM_APP_START % DAPLINK_MIN_WRITE_SIZE == 0);
 // Application size must be a multiple of write size
@@ -42,6 +43,7 @@ COMPILER_ASSERT(DAPLINK_ROM_APP_START % DAPLINK_SECTOR_SIZE == 0);
 COMPILER_ASSERT(DAPLINK_ROM_UPDATE_START % DAPLINK_SECTOR_SIZE == 0);
 // Update size must be a multiple of sector size
 COMPILER_ASSERT(DAPLINK_ROM_UPDATE_SIZE % DAPLINK_SECTOR_SIZE == 0);
+#endif
 
 typedef enum {
     STATE_CLOSED,
diff --git a/source/hic_hal/nordic/nrf52840/daplink_addr.h b/source/hic_hal/nordic/nrf52840/daplink_addr.h
index d1a00ef18a..b89337d82e 100644
--- a/source/hic_hal/nordic/nrf52840/daplink_addr.h
+++ b/source/hic_hal/nordic/nrf52840/daplink_addr.h
@@ -24,14 +24,11 @@
 #define DAPLINK_ROM_START               0x00000000
 #define DAPLINK_ROM_SIZE                0x00040000 // 256 KiB
 
-
 #define DAPLINK_RAM_START               0x20000000
 #define DAPLINK_RAM_SIZE                0x00010000 // 64 KiB
 
 /* ROM sizes */
 
-
-
 #define DAPLINK_ROM_BL_START            0x00000000
 
 #if !defined(NRF_SECURE_BOOTLOADER)
@@ -51,12 +48,13 @@
 
 #else // NRF_SECURE_BOOTLOADER
 
-#define DAPLINK_ROM_BL_SIZE             0x00013000 // 76 KiB MCUBOOT
-#define DAPLINK_ROM_IF_START            0x00013000
-#define DAPLINK_ROM_IF_SIZE             0x0002C000
+#define DISABLE_FLASH_INTF_CHECKS
+#define DAPLINK_ROM_BL_SIZE             NRF_SECURE_BOOTLOADER_OFFSET // MCUBOOT
+#define DAPLINK_ROM_IF_START            NRF_SECURE_BOOTLOADER_OFFSET
+#define DAPLINK_ROM_IF_SIZE             (0x00040000-NRF_SECURE_BOOTLOADER_OFFSET)
 
 #define NON_CONTIGUOUS_USER_CONFIG
-#define DAPLINK_ROM_CONFIG_USER_START   0x000F7000
+#define DAPLINK_ROM_CONFIG_USER_START   0x000FE000
 #define DAPLINK_ROM_CONFIG_USER_SIZE    0x00001000
 
 #endif
diff --git a/source/hic_hal/nordic/nrf52840/gcc/gcc_startup_nrf52840.S b/source/hic_hal/nordic/nrf52840/gcc/gcc_startup_nrf52840.S
index 1eb57971c7..6ecf28fcbc 100644
--- a/source/hic_hal/nordic/nrf52840/gcc/gcc_startup_nrf52840.S
+++ b/source/hic_hal/nordic/nrf52840/gcc/gcc_startup_nrf52840.S
@@ -197,6 +197,13 @@ Reset_Handler:
 .L_loop1_done:
 #endif
 
+#ifdef NRF_SECURE_BOOTLOADER
+    movs r3, #0
+    msr	CONTROL, r3
+    msr	PSP, r3
+    msr	PRIMASK, r3
+#endif
+
 /* This part of work usually is done in C library startup code. Otherwise,
  * define __STARTUP_CLEAR_BSS to enable it in this startup. This section
  * clears the RAM where BSS data is located.