[UMI Z] Network connection out of order

Mans30

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Hi folks,

I had to repair a broken screen followed by a factory reset to make sure the phone was clean. Strangely, everything works well except the network connexion. The SIM card is recognized, the APN config is OK, the mobile number is displayed in the device parameters / about phone / Status / SIM card Status. It just stays disconnected and never find any network. I mean the mobile network. The wifi works well, the bluetooth too. I checked with another SIM card that works on another phone, same result. I tried on the 2nd SIM slot. Guess...same.

I tried to flash the latest ROM 7.1.1, thinking a new modem firmware could help. My IMEI numbers were erased but I corrected it as explained here. I didn't make any difference regarding the network issue. Then I flashed back the official 6.0 ROM with another factory reset just to be "out of the box".

Now I wonder :
- After those flashes, do I still have a valid android efs directory because I can't find it clearly with root explorer. Anyone knows what I could check to be sure ?
- Did I make a mistake while repairing the screen because it requires to unplug many tiny components. Maybe the modem is not well plugged ? Or the antenna ? Anyone knows how to locate those parts ?
- The android anti-theft option was activated on the phone and it blocked me when I restarted the device after the screen replacement. I tried several times before remembering the special PIN code to unlock this option. Could my device be blacklisted ? How could I check this ?

I bought this phone on presale in january for my daughter, got it for her birthday on february and it's now unusable if she can't make any phone call or text message. Of course, because the screen has been replaced, the warranty is void.

Thanks for your help.

eboury

Anyone could at least show me a screenshot of what the efs directory should look like ?

Medard22

Hi there, as you describe the problem it seems like an issue made during the screen replacement, probably a disconnected or damaged antenna. I am not sure if the Umi actually uses EFS partition at all. It has a several partitions holding system data like nvram and others. You can see them in SPFT flash tool or TWRP. Anyway during SPFT upgrade all these partitions are flashed, so that shouldn´t be the issue. I remember there was a glitch when upgrading from MM to Nougat with SPFT that the IMEI numbers are wiped, but you recovered them so that shouldn´t be an issue.
I would definitely open up the phone again and double check the antenna connection.

Sad

Looks can be with this picture, looks if everything seems to you identical, it can help you

Sad

Have you plugged in the small cable that passes along the battery, on the iphone C will be the GSM antenna, in case

eboury

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Great thx for your help, Medard22 and Sad. I'll check again the connexions, then. I know I had a hard time when I unplugged the antenna cable when I dismantled it the 1st time. That could be the issue.

I'll come back with the result.

eboury

I've tried again to reconnect all cables, including the 2 antenna plugs but nothing better. It all looks fine, I don't know what to try next.

I had to reflash the rom with spft and did a factory reset by the way because it couldn't start after that.

Medard22

I really can´t help you much further unfortunately. It really doesn´t look like a software issue. You might try to tinker with the service menu, check the status of the radio. The antenna connector could be damaged, or something was shorted during the repair process. I would consider local phone service center where they could check the phone and antenna connections.

Mans30

\n\nMistake, sorry

eboury

I couldn't find any local service accepting to check an UMI phone. They don't even know what it is. I'll try some other places but not sure I'll find any.

By the way, I've noticed something strange about the serial number displayed in the parameters. Can anyone check if they have a "real" serial number or if it's like mine ? If it's a real number, how can I find it on the phone package ? There's a sticker on the box with many numbers including the 2 IMEI but I don't know which of the others is the serial number. Maybe I need to reset it to the real value to make it work...