diff --git a/arch/arm/cpu/arm920t/Makefile b/arch/arm/cpu/arm920t/Makefile
index 1832b9d..7aa432a 100644
--- a/arch/arm/cpu/arm920t/Makefile
+++ b/arch/arm/cpu/arm920t/Makefile
@@ -16,6 +16,6 @@
 
 # some files can only build in ARM mode
 
-ifdef CONFIG_SYS_THUMB_BUILD
+ifdef CONFIG_$(SPL_)SYS_THUMB_BUILD
 CFLAGS_cpu.o := -marm
 endif