diff --git a/tools/boot/wheezy/common.sh b/tools/boot/wheezy/common.sh
index 90e37c01..27c72340 100644
--- a/tools/boot/wheezy/common.sh
+++ b/tools/boot/wheezy/common.sh
@@ -96,7 +96,7 @@ calc_boot_size() {
 # Grab the xorriso version and turn it into a number we can use
 xorriso_version() {
     $MKISOFS --version 2>&1 | awk '
-       `/^xorriso version/ {
+       /^xorriso version/ {
            split($4, ver, ".")
            print ver[1]*10000+ver[2]*100+ver[3]
        }'