diff --git a/meta/conf/machine/include/arm/feature-arm-thumb.inc b/meta/conf/machine/include/arm/feature-arm-thumb.inc
index b5801687fa..e7d392e95a 100644
--- a/meta/conf/machine/include/arm/feature-arm-thumb.inc
+++ b/meta/conf/machine/include/arm/feature-arm-thumb.inc
@@ -5,7 +5,8 @@
 # but requires more instructions (140% for 70% smaller code) so may be
 # slower.
 TUNEVALID[thumb] = "Use thumb instructions instead of ARM"
-TUNE_CCARGS += "${@bb.utils.contains("TUNE_FEATURES", "thumb", "-mthumb", "-mno-thumb", d)}"
+ARM_THUMB_M_OPT = "${@['-mno-thumb', '-mthumb'][bb.data.getVar('ARM_INSTRUCTION_SET', d, 1) == 'thumb']}"
+TUNE_CCARGS += "${@bb.utils.contains("TUNE_FEATURES", "thumb", "${ARM_THUMB_M_OPT}", "${ARM_THUMB_M_OPT}", d)}"
 OVERRIDES .= "${@bb.utils.contains("TUNE_FEATURES", "thumb", ":thumb", "", d)}"
 
 # Note armv7 will hit on armv7a as well