diff --git a/pkgs/build-support/kernel/make-initrd.sh b/pkgs/build-support/kernel/make-initrd.sh
index 5c63856c19f..d930e51a03f 100644
--- a/pkgs/build-support/kernel/make-initrd.sh
+++ b/pkgs/build-support/kernel/make-initrd.sh
@@ -36,4 +36,4 @@ storePaths=$(perl $pathsFromGraph closure-*)
 
 # Put the closure in a gzipped cpio archive.
 ensureDir $out
-(cd root && find * -print0 | cpio -ov -H newc --null | bzip2 -9 > $out/initrd)
+(cd root && find * -print0 | cpio -ov -H newc --null | gzip -9 > $out/initrd)