--- afboot-stm32-3566acd582e5536fb60864281788a30f5527df2d.orig/Makefile	2020-11-11 22:52:18.000000000 +0100
+++ afboot-stm32-3566acd582e5536fb60864281788a30f5527df2d/Makefile	2020-11-11 22:56:16.737522477 +0100
@@ -13,6 +13,7 @@ DTB_ADDR?=0x08004000
 CFLAGS := -mthumb -mcpu=cortex-m4
 CFLAGS += -ffunction-sections -fdata-sections
 CFLAGS += -Os -std=gnu99 -Wall
+CFLAGS += -fno-builtin -mno-fdpic
 LINKERFLAGS := -nostartfiles --gc-sections
 
 obj-y += gpio.o mpu.o qspi.o start_kernel.o