[Galaxy S6 Q&A, Help & Troubleshooting] ozimandis:
Samsung S6 No Network Fix

Hello to all my friends,

Sorry for my bad English.I had some bad experience as all of you,but I have managed to fix my phone.

In my quest most helpful were information and data I have found on the Internet.Now that I have fixed my phone I thought it is my time to pay back favor to society.

My cousin got phone Samsung Galaxy SMG920 F and have used it for about a year.When his contract ended he decided to unlock phone so he could use it on different network.

Guys at some phone service shop have done it for 1000 din - or 10 $ in USD. Anyway after that problem started to show up.

No network no signal even with his original SIM card. He gave it to some service shops but no help. Four different shops for repair returned it to him with simple explanation:

There is no help,motherboard is gone,probably baseband chip has overheated and died.So my cousin bought Samsung S8 and gave me S6 as present.

So considering I was on sick leave and had no cash for new phone I started to play with my new toy.

When I first booted phone he had original software but knox tripped and rooted. Camera and network did not work,not even WIFI.

I flash Lineage OS 14.1 and it helped I got stable OS but no network signal.Typed *#06# and got IMEI null and in about phone software version there is no baseband version.

So I read a lot and got to conclusion that EFS partition is damaged and I needed to restore it.But how when I did not had backup file.My solution was to download it from net and restore it.

Even though I downloaded right version for my phone it was HUGE mistake,at least in my case.After the reboot phone did not want to start neither to flash.

Always same error: failed to mount /efs (Invalid argument) or something like that.I have found a solution on network. I used ADB shell and typed certain commands.

Instruction was type ADB SHELL then ENTER and then mke2fs /dev/block/mmcblk0p3 then ENTER and then mount -w -t ext4 /dev/block/mmcblk0p3 and finally reboot.

It did not work,at least until I have figured out that for Samsung G920F you should change that mmcblk0p3 text part with SDA3.(Note for ADB to work you should be in TWRP and choose mount system).

Than I was able to flash again and boot in OS.After boot my IMEI was 350000000000006 signal strength good and got baseband version,but still no signal error and can not connect to any network.

So I have followed these steps.

SOLUTION:

1.FLASH STOCK FIRMWARE (USING ODIN)

(DOWNLOAD AT SAMMOBILE OR BY USING SAMFIRM)

2.FLASH CHAINFIRE ROOT TO BYPASSE DRK IS MISSING ERROR AND TO GAIN ROOT ACCESS (USING ODIN)

3.FLASH TWRP (USING ODIN)

4.INSTALL BUSY BOX (JUST IN CASE)

4.USE TOOL Z3X (ALSO KNOWN AS SAMSUNG TOOL PRO,I USED CRACKED 29.5 VERSION)

5.RESET EFS

6.WRITE NV-DATA-DOWNLOAD IT FROM GOOGLE (STRANGELY ONLY ACCEPT NV DATA FOR MODEL SM-G920T DOES NOT ACCEPT NV DATA FOR MODEL SM-G920F)

7.REPAIR IMEI (write one from back off your phone or on the battery or on the phone box)

8.WRITE CERT FILE - DOWNLOAD IT FROM GOOGLE

9.UNLOCK (IF IT IS LOCKED TO CERTAIN NETWORK)

It will reboot and start normally.Everything working fine.That is it,summary.

Some more helpful tips.Open cert files with notepad++ to see are they ok or if there are just zeros or some crap,but do not modify it in any way.

Even though this is SM-G920F some option in Z3X worked only if I chose SM-G920T model. It is all about try and error.There will be pop up warnings wrong version selected there will be damage if continue but do not worry.

In some countries changing IMEI is Illegal be advised.Also if you brick your device it is not my fault.As I said this is all try and error,these are uncharted waters and there is always risk.Just read and read and google and google it.

For every problem there is a solution. And be brave and good luck my friends.