diff --git a/config.json b/config.json
index 9d4f031..9cb8693 100644
--- a/config.json
+++ b/config.json
@@ -35,8 +35,8 @@
         "SDKMACHINE" : "x86_64",
         "PACKAGE_CLASSES" : "package_rpm package_deb package_ipk",
         "DLDIR" : "DL_DIR = '${BASE_SHAREDDIR}/current_sources'",
-        "SSTATEDIR" : ["SSTATE_DIR ?= '${BASE_SHAREDDIR}/pub/sstate'"],
-        "SSTATEDIR_RELEASE" : ["SSTATE_DIR ?= '${BASE_SHAREDDIR}/pub/sstate'"],
+        "SSTATEDIR" : ["SSTATE_DIR = '${BASE_SHAREDDIR}/pub/sstate'"],
+        "SSTATEDIR_RELEASE" : ["SSTATE_DIR = '${BASE_SHAREDDIR}/pub/sstate'"],
         "SDKEXTRAS" : ["SSTATE_MIRRORS += '\\", "file://.* http://sstate.yoctoproject.org/all/PATH;downloadfilename=PATH'", "BB_HASHSERVE = 'auto'", "BB_HASHSERVE_UPSTREAM = '${AUTOBUILDER_HASHSERV}'"],
         "BUILDINFO" : false,
         "BUILDHISTORY" : false,
@@ -191,7 +191,7 @@
         },
        "bringup" : {
             "BUILDINFO" : true,
-            "SSTATEDIR" : ["SSTATE_DIR ?= '${HELPERBUILDDIR}/sstate'"],
+            "SSTATEDIR" : ["SSTATE_DIR = '${HELPERBUILDDIR}/sstate'"],
             "MACHINE" : "qemuarm64",
              "step1" : {
                  "SDKMACHINE" : "x86_64",
@@ -230,8 +230,8 @@
         },
         "buildperf" : {
             "MACHINE" : "qemux86",
-            "SSTATEDIR" : ["SSTATE_DIR ?= '${HELPERBUILDDIR}/sstate'"],
-            "SSTATEDIR_RELEASE" : ["SSTATE_DIR ?= '${HELPERBUILDDIR}/sstate'"],
+            "SSTATEDIR" : ["SSTATE_DIR = '${HELPERBUILDDIR}/sstate'"],
+            "SSTATEDIR_RELEASE" : ["SSTATE_DIR = '${HELPERBUILDDIR}/sstate'"],
             "PACKAGE_CLASSES" : "package_rpm",
             "EXTRAPLAINCMDS" : [
                 "${SCRIPTSDIR}/build-perf-test-wrapper --results-dir ${BUILDPERF_RESULTSDIR} --email-addr yocto-perf@lists.yoctoproject.org --download-dir ${BUILDPERF_STATEDIR}/downloads --publish-dir ${HELPERRESULTSDIR}/${HELPERTARGET} --repo ${HELPERREPONAME} --branch ${HELPERBRANCHNAME} --push-remote git@push.yoctoproject.org:yocto-buildstats --build-dir ${HELPERBUILDDIR}"
@@ -677,7 +677,7 @@
             }
         },
        "bringup" : {
-            "SSTATEDIR" : ["SSTATE_DIR ?= '${HELPERBUILDDIR}/sstate'"],
+            "SSTATEDIR" : ["SSTATE_DIR = '${HELPERBUILDDIR}/sstate'"],
             "TEMPLATE" : "bringup"
         },
        "bringup-fast" : {