I've installed update.zip (from download.clockworkmod.com) via the recovery, /system/xbin/su file exists:
$ ls -l /system/xbin/su
-rwsr-sr-x root root 311872 2015-12-28 00:28 su
But it doesn't work:
shell@lt033g:/ $ su
255|shell@lt033g:/ $ id
uid=2000(shell) gid=2000(shell) groups=1003(graphics),1004(input),1007(log),1011(adb),1015(sdcard_rw),1028(sdcard_r),3001(net_bt_admin),3002(net_bt),3003(inet),3006(net_bw_stats) context=u:r:shell:s0
shell@lt033g:/ $
Why? I'm using Samsung Galaxy Note 10.1 2014, Android 4.4.2
P.S. I can not use SuperSU for some reasons, I can use SuperUser only.