[Samsung Galaxy J7 Guides, News, & Discussion] timmetal6669:
Team RejectZ

How to Nandroid Back up and Restore as well as flash zips with TWRP on the Galaxy J700t1 (Metro PCS variant)

Hello , TimmetaL6669 here from Team Rejectz... It feels so good to be back.. So we have been having this little problem with the TWRP when it comes to doing a back up or flash anything because of, "system can't mount -data , failed" "system can't mount external sd card " .. or something along those lines... So after playing with it for awhile I finally figured out what the problem is... We are used to the old file system before Marshmallow... Before Marshmallow and before SE Linux Enforced the system would write directly to data or the sd card by mounting it directly... but with the new security the system writes through the system.. not by mounting thus avoiding potential malware attacks... so if the system can write to itself... so can we... This fix is more simple than I originally thought... there is no need to mount data unless you are flashing a ROM in which case we can use odin....or TWRP... you just have to know from where...So without further adue,

Pre-Requisites:

You must be Rooted usisng Mese2050's ported TWRP recovery and flashing SU binaries or by using Paco's Method.

You must have a micro SD card with at least 4 GB on it for your zips and backups

WARNINGS: DO NOT WIPE DATA OR CASHE OR DALVIK CASHE FOR ANY REASON YOU WILL END UP IN A BOOT LOOP OR AT THE RESTORE SCREEN

There isn't any reason to change cashe or data unless you are doing a full ROM change ..... Odin does this anyway when you odin so unless you just made an entire ROM with kernel and recovery included with STOCK cashe then DON'T WIPE CASHE OR DATA on marshmallow.. New security.. They did away with us messing with DATA or CASHE.... No need anyway for a back up or restore or to flash zips.... a good updater script for zips for marshmallow will mount the System anyway.

To Nandroid Back UP:

1. Boot into TWRP and click BACK UP. You're gonna need to switch your storage.... Switch your storage to Micro SDCard STORAGE .. because thats where we are going to be making our backup to..Then Swipe to Back up. Wait for your backup to be complete

To Nandroid RESTORE:

Boot into TWRP. Click RESTORE. This time though we have been running into the "can't mount storage/ can't mount data" issue ...So..... Instead of switching to your Micro SDCard storage, STAY IN INTERNAL STORAGE. click "go up a level". Click external SD. Find your back up and swipe to Restore.

To Flash zip Files

Again just like with the restore option we are going to stay in the internal storage and click "go up a level" click external sd card and find the zip file you want to flash from your sd card. Click install Image

Thats it. Click thanks if I helped you, Feel free to ask questions if you get stuck. Make sure that you are completely rooted first with SU and Busybox binaries in /system/bin , /system/xbin and root/sbin before you try to use TWRP. Before attempting a back up, or to use TWRP make sure you follow the instructions carefully in Mese2050's TWRP thread.

" Go to [Wipe] -> [Format Data] (not advanced wipe) -> type "yes".

WARNING: This will wipe your internal storage, disable encryption, and factory reset your phone!

Go to [Reboot] -> [Recovery]."

Also ensure that you have "unknown sources" checked in Settings/Security tab. and also in "Developer Options" you wanna have USB debugging and OEM unlock checked too.