diff --git a/package/base-files/files/etc/uci-defaults/12_network-generate-ula b/package/base-files/files/etc/uci-defaults/12_network-generate-ula
index 19d7ed7f2e..060d0ef640 100644
--- a/package/base-files/files/etc/uci-defaults/12_network-generate-ula
+++ b/package/base-files/files/etc/uci-defaults/12_network-generate-ula
@@ -1,11 +1,7 @@
 [ "$(uci -q get network.globals.ula_prefix)" != "auto" ] && exit 0
 
-r1=$(dd if=/dev/urandom bs=1 count=1 |hexdump -e '1/1 "%02x"')
-r2=$(dd if=/dev/urandom bs=2 count=1 |hexdump -e '2/1 "%02x"')
-r3=$(dd if=/dev/urandom bs=2 count=1 |hexdump -e '2/1 "%02x"')
-
 uci -q batch <<-EOF >/dev/null
-	set network.globals.ula_prefix=fd$r1:$r2:$r3::/48
+	set network.globals.ula_prefix="$(hexdump -vn 5 -e '"fd" 1/1 "%02x:" 2/2 "%x:"' /dev/urandom):/48"
 	commit network
 EOF