diff --git a/conf/distro/include/tcmode-external-sourcery-rebuild-libc.inc b/conf/distro/include/tcmode-external-sourcery-rebuild-libc.inc
index b97fd30..b7dd1d2 100644
--- a/conf/distro/include/tcmode-external-sourcery-rebuild-libc.inc
+++ b/conf/distro/include/tcmode-external-sourcery-rebuild-libc.inc
@@ -5,5 +5,5 @@ PREFERRED_PROVIDER_virtual/libiconv = "eglibc-sourcery"
 PREFERRED_PROVIDER_virtual/libintl = "eglibc-sourcery"
 PREFERRED_PROVIDER_virtual/${TARGET_PREFIX}libc-for-gcc = "eglibc-sourcery"
 PREFERRED_PROVIDER_eglibc = "eglibc-sourcery"
-CSL_SRC_URI ??= "file://${CSL_SRC_FILE}"
-CSL_SRC_FILE ??= "${@bb.fatal('Please set CSL_SRC_FILE to the path to your sourcery src tarball')}"
+CSL_SRC_URI ?= "file://${CSL_SRC_FILE}"
+CSL_SRC_FILE ?= "${@bb.fatal('Please set CSL_SRC_FILE to the path to your sourcery src tarball')}"
diff --git a/recipes/eglibc/eglibc-sourcery.bb b/recipes/eglibc/eglibc-sourcery.bb
index bdb5818..8616c20 100644
--- a/recipes/eglibc/eglibc-sourcery.bb
+++ b/recipes/eglibc/eglibc-sourcery.bb
@@ -5,7 +5,7 @@ PROVIDES += "eglibc"
 TOOLCHAIN_OPTIONS = ""
 
 # sourceryg++-${CSL_VER_MAIN}-${CSL_TARGET_SYS}.src.tar.bz2
-CSL_SRC_URI ??= ""
+CSL_SRC_URI ?= ""
 SRC_URI = "${CSL_SRC_URI} \
            file://etc/ld.so.conf \
            file://generate-supported.mk"
@@ -56,8 +56,8 @@ do_configure () {
 
 require recipes/eglibc/eglibc-package-adjusted.inc
 
-CSL_VER_MAIN ??= ""
-CSL_VER_LIBC ??= ""
+CSL_VER_MAIN ?= ""
+CSL_VER_LIBC ?= ""
 
 python () {
     if not d.getVar("CSL_VER_MAIN"):