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SIM Card not working after Flashing Official Stock ROM(Read below for important note!)

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mottaM

Member
Jul 25, 2021
16
1
Actually I bricked my device and I was trying to flash the stock ROM again using SP Flash tool. Unfortunately while flashing it shows sec_aut_mismatch ( or something like this) for the file called cust.img in the stock rom and says please disable verified boot. What I did now is "why don't I try letting it go?" I unchecked it. I flashed rom without this file. it got flashed, works fine everything except SIM Cards. The phone detects sim cards but no signal. SIm cards are fine Physically. Do you believe that this not flashing cust.img could be a cause?
MAIN THING: Flashed Stock Rom without CUST.IMG
Secondly I tried to flash the cust.img using fastboot now, but still no luck. I don't know what this file does. PLEASE HELP ME. I AM IN TROUBLE
 

mottaM

Member
Jul 25, 2021
16
1
Actually I bricked my device and I was trying to flash the stock ROM again using SP Flash tool. Unfortunately while flashing it shows sec_aut_mismatch ( or something like this) for the file called cust.img in the stock rom and says please disable verified boot. What I did now is "why don't I try letting it go?" I unchecked it. I flashed rom without this file. it got flashed, works fine everything except SIM Cards. The phone detects sim cards but no signal. SIm cards are fine Physically. Do you believe that this not flashing cust.img could be a cause?
MAIN THING: Flashed Stock Rom without CUST.IMG
Secondly I tried to flash the cust.img using fastboot now, but still no luck. I don't know what this file does. PLEASE HELP ME. I AM IN TROUBLE
A thing I forgot is that cust.img flash is successful in fastboot mode
 

dedq

Senior Member
May 14, 2015
374
2
357
Belgrade
I have a little backup taken through twrp. But it has only some files starting with boot, bootloader and recovery. Total 9 files. Can you explain more about EFS please?
EFS is something responsible for your IMEI which is connected to the signal and SIM.
You cannot have phone signal if you don't have IMEI number which you could have lost. Can you check if you have IMEI? If not, the problem is probably in modem and I would be happy if you had backed that up.
 

mottaM

Member
Jul 25, 2021
16
1
EFS is something responsible for your IMEI which is connected to the signal and SIM.
You cannot have phone signal if you don't have IMEI number which you could have lost. Can you check if you have IMEI? If not, the problem is probably in modem and I would be happy if you had backed that up.
I don't see any IMEI numbers. A little research tells me that I must have nvdata.bin and nvram.img in the backup. If this is correct then I don't have such a backup. Is there any way to fix it up without backup?
 

mottaM

Member
Jul 25, 2021
16
1
EFS is something responsible for your IMEI which is connected to the signal and SIM.
You cannot have phone signal if you don't have IMEI number which you could have lost. Can you check if you have IMEI? If not, the problem is probably in modem and I would be happy if you had backed that up.
One more thing I notice is that when I enter Recovery mode, It says "nvdata corrupt" in red. More information you may want to know is:
My device is redmi 6a
Wifi works fine
Baseband version present
When I insert sim cards, it detects them(icons get updated on the notification area) it also says getting sim info.
When I enter phone information, it says signal strength in those numbers when sim is inserted

I believe that hardware is fine thus. I really regret my step of trying to change OS. I just want to get sim working somehow
 

dedq

Senior Member
May 14, 2015
374
2
357
Belgrade
I don't see any IMEI numbers. A little research tells me that I must have nvdata.bin and nvram.img in the backup. If this is correct then I don't have such a backup. Is there any way to fix it up without backup?
I have never had that kind of problem and only had problems with EFS.
I think flashing stock ROM would fix your problem. I don't know what else could be.
 

jwoegerbauer

Senior Member
Jul 11, 2009
6,794
19
1,587
European Union
Actually I bricked my device and I was trying to flash the stock ROM again using SP Flash tool. Unfortunately while flashing it shows sec_aut_mismatch ( or something like this) for the file called cust.img in the stock rom and says please disable verified boot. What I did now is "why don't I try letting it go?" I unchecked it. I flashed rom without this file. it got flashed, works fine everything except SIM Cards. The phone detects sim cards but no signal. SIm cards are fine Physically. Do you believe that this not flashing cust.img could be a cause?
MAIN THING: Flashed Stock Rom without CUST.IMG
Secondly I tried to flash the cust.img using fastboot now, but still no luck. I don't know what this file does. PLEASE HELP ME. I AM IN TROUBLE

You should know that EFS ( NVRAM ) is a partition on your Android device that stores all the important data associated with your phone. For instance, these data include the IMEI number, Mac address of Wireless devices, important files of internet and product code, etc. Moreover, this data is so important that without this, you would not be able to use your Android phone. And it is very important to keep this partition safe and backed up in case things go south.

My guess is because you were flashing custom ROMs and/or modded apps that you have lost this important EFS ( NVRAM ) partition on the device.
 
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