diff --git a/package/musl/musl.mk b/package/musl/musl.mk
index 081a700286..733f940db2 100644
--- a/package/musl/musl.mk
+++ b/package/musl/musl.mk
@@ -23,6 +23,12 @@ MUSL_ADD_TOOLCHAIN_DEPENDENCY = NO
 
 MUSL_INSTALL_STAGING = YES
 
+# Thumb build is broken, build in ARM mode, since all architectures
+# that support Thumb1 also support ARM.
+ifeq ($(BR2_ARM_INSTRUCTIONS_THUMB),y)
+MUSL_EXTRA_CFLAGS += -marm
+endif
+
 define MUSL_CONFIGURE_CMDS
 	(cd $(@D); \
 		$(TARGET_CONFIGURE_OPTS) \