diff --git a/package/mpir/mpir.mk b/package/mpir/mpir.mk
index 91f704d30c..5dbd760aa1 100644
--- a/package/mpir/mpir.mk
+++ b/package/mpir/mpir.mk
@@ -36,4 +36,8 @@ ifeq ($(BR2_powerpc64le),y)
 MPIR_CONF_ENV += MPN_PATH="generic"
 endif
 
+ifeq ($(BR2_ARM_INSTRUCTIONS_THUMB),y)
+MPIR_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -marm"
+endif
+
 $(eval $(autotools-package))