diff --git a/script/build/release/roms b/script/build/release/roms
index 7be63e6d..c86fc79f 100755
--- a/script/build/release/roms
+++ b/script/build/release/roms
@@ -131,7 +131,7 @@ make_archive()
 	f="release/${version}/roms/${archivename}"
 	(
 	cd "${romdir%/bin/${target}}" || err "make_archive: can't cd to tmpdir"
-	tar -c "bin/${target}/" | xz -9e > "${archivename}.tar.xz" || \
+	tar -c "bin/${target}/" | xz -T0 -9e > "${archivename}.tar.xz" || \
 	    err "make_archive:cant make ${projectname}-${version}_${target##*/}"
 	)
 	cp "${romdir%/bin/${target}}/${archivename}.tar.xz" "${f}.tar.xz" || \
diff --git a/script/build/release/src b/script/build/release/src
index db737d2d..4d5c3efe 100755
--- a/script/build/release/src
+++ b/script/build/release/src
@@ -196,7 +196,7 @@ create_release_archive()
 	    err "create_release_archive: can't create ${dirname}/versiondate"
 	printf "%s\n" "${projectname}" > "${dirname}/projectname" || \
 	    err "create_release_archive: can't create ${dirname}/projectname"
-	tar -c "${dirname}/" | xz -9e >"${dirname}.tar.xz" || \
+	tar -c "${dirname}/" | xz -T0 -9e >"${dirname}.tar.xz" || \
 	    err "create_release_archive: can't create ${dirname}.tar.xz"
 	rm -Rf "${dirname}/" || \
 	    err "create_release_archive 5: !rm -Rf ${dirname}/"