diff --git a/thunks/Makefile b/thunks/Makefile
index 891ca1f..27ba55d 100644
--- a/thunks/Makefile
+++ b/thunks/Makefile
@@ -31,5 +31,5 @@ fel-to-spl-thunk.h: fel-to-spl-thunk.S FORCE
 	$(OBJDUMP) -d $(subst .S,.o,$<) | $(AWK_O_TO_H) -v style=old > $@
 
 $(THUNKS): %.h: %.S FORCE
-	$(AS) -o $(subst .S,.o,$<) $<
+	$(AS) -o $(subst .S,.o,$<) -march=armv5te $<
 	$(OBJDUMP) -d $(subst .S,.o,$<) | $(AWK_O_TO_H) > $@
diff --git a/thunks/rmr-thunk.S b/thunks/rmr-thunk.S
index 10429b5..7d67ccc 100644
--- a/thunks/rmr-thunk.S
+++ b/thunks/rmr-thunk.S
@@ -1,6 +1,8 @@
 /*
  * Request AArch32/AArch64 warm reset, using RVBAR and Reset Management Register
+ * This is used on ARMv8 cores only, so force v7 code to allow dsb and isb.
  */
+.arch	armv7-a
 
 rmr_request:
 	ldr	r0, 1f	/* RVBAR register address */