[Q] N915s cannot mounting /system topic

Hi all

I got a issues which cannot flash any rom in to my N915s

with the step as below in odin 3.07
1. CF-Auto-Root-tbelteskt-tbelteskt-smn915s.zip
2. n915s-cwm-recovery-6.0.5.1(1126)
After that my N915s got rooted, and work fine.

But I try to flash custom rom in cwm, is only show update, then the phone auto rebooted, there are nothing and return back to old rom.

After I check that, is seems cannot mount the /system, and I try to manual mount /system but return error mounting /system.
I try to do it again with CF-Auto-Root > CWM but still no luck.

Now I don't have any idea, please help....