--- toolchain.eclass.orig	2012-10-01 02:31:14.000000000 -0300
+++ toolchain.eclass	2012-10-30 01:03:35.523023216 -0300
@@ -947,6 +947,11 @@
 			then
 				confgcc+=" --with-arch=${arm_arch}"
 			fi
+			
+			# If arch is armv7-m, use thumb mode only.
+			if [[ ${arm_arch} == "armv7-m" ]] ; then
+				confgcc+=" --with-mode=thumb"
+			fi
 
 			# Enable hardvfp
 			if [[ $(tc-is-softfloat) == "no" ]] && \