diff --git a/boards/nordic/thingy53/Kconfig.sysbuild b/boards/nordic/thingy53/Kconfig.sysbuild
index 512df68ab68..df489c1dd54 100644
--- a/boards/nordic/thingy53/Kconfig.sysbuild
+++ b/boards/nordic/thingy53/Kconfig.sysbuild
@@ -20,6 +20,9 @@ config NETCORE_APP_UPDATE
 config NRF_DEFAULT_EMPTY
 	default y if SECURE_BOOT_NETCORE
 
+config MCUBOOT_USE_ALL_AVAILABLE_RAM
+	default y if BOARD_THINGY53_NRF5340_CPUAPP_NS && BOOTLOADER_MCUBOOT
+
 endif # BOARD_THINGY53_NRF5340_CPUAPP || BOARD_THINGY53_NRF5340_CPUAPP_NS
 
 config PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY