diff --git a/package/gmp/gmp.mk b/package/gmp/gmp.mk
index 5eb6ecc6ee..2222465c8f 100644
--- a/package/gmp/gmp.mk
+++ b/package/gmp/gmp.mk
@@ -9,5 +9,10 @@ GMP_SITE = $(BR2_GNU_MIRROR)/gmp
 GMP_SOURCE = gmp-$(GMP_VERSION).tar.bz2
 GMP_INSTALL_STAGING = YES
 
+# Bad ARM assembly breaks on pure thumb
+ifeq ($(ARCH),arm)
+GMP_MAKE_OPT += CFLAGS="$(TARGET_CFLAGS) -marm"
+endif
+
 $(eval $(call AUTOTARGETS))
 $(eval $(call AUTOTARGETS,host))