Weird problem with modems: "Unknown" baseband, IMEI, etc.

Hi!

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My note has some weird problem with the modems. I'm getting "Unknown" baseband, modem verison, phone number, IMEI etc. with all the modems I tried except one, which shows the correct IMEI and modem version but still not working(I can even see the mobile networks with that one, but I it doesn't connect and gives me "Refresing SIM data" messages).

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I always have been using custom roms(only TW) and updating my note to the latest version and I never had a problem.
One day, some months after the last rom update, started to lose the phone network conection and I was getting pop-ups with "Refreshing SIM data"(was very annoying because that was turning on the phone screen every few minutes). Sometimes I had phone network and sometimes I hadn't. The disconnections became more frequently. The phone also started to eat up the free space for apps, so I had to remove several apps to install or update even a small one.
So I decided to change to a different ROM to see if that fixes both problems, but I got the actual problem.

I was in AllianceRom v3 JB when that happened.
I flashed this AryaMod 5.5 JB following their instructions and I got this weird problem. In the "About phone" says that the Baseband version, IMEI, IMEI SV, Network and My phone number are "Unknown". I can't even search for mobile networks because it says "Insert SIM card" when I try to open the Mobile networks menu. Tehre are no signal bars, only a "denied" icon on the status bar.
I tested all JB modems and some from ICS from the "all modems" thread, but I was getting the same "Unknown" things in each one, except the XXLSO, where the Baseband version, IMEI and IMEI SV were okey. I could also find mobile networks with this modem, and the "Refreshing SIM data" thing returned, but it was not possible to connect to a network. With this one, there aresignal bars, but they are empty.
I flashed the AllianceRom and even the old ICS rom I had before, but the problem persisted, even with the modems they came with.
Now I'm on the latest Samsung rom(LT4), unmodified and flashed with odin and the problem persist.

I found this old thread. His initial problem is very similar to mine, but they don't know what caused it nor how to fix it.
I have also found something about corruped IMEIs that you can fix doing something with the ADB and restoring EFS folder, but I think that is not my case because I can see my original IMEI with the XXLSO modem (and I my EFS folder looks OK, anyway I have no backup of that).

I don't expect to get a step-by-step tutorial about how to fix this, but I hope somebody can put me in the right direction. I will post the solution if I find one!

Thanks for reading, the four first digits are 3595.

I tried both. Also I have been using the SIM with another phone for weeks and works fine. Tried to take out the battery and wait few minutes and other "stupid" things like re-flash a ROM, re-wipe all, etc..

Maybe it's the programed obsolescence, you can use the Note as PDA but if you want a phone, go and buy another...

I have no backup of efs... I had one "nandroid" but deleted it after everything was okey...
I could delete the efs folder, so this unknown problem will turn a known one :victory:

I dropped the phone a very few times, maybe in one of those something broke a little and has increased more with the usage? (the disconnections from the network became spontaneus and progressively).

I found this other thread, I could try the same but I can't find the original GB firmware, every link I find is in hotfile.

I found a efs backup from may 2012, probably auto-created when first installed ICS.
I flashed the stock GB rom and restored it following this tutorial for my .tar.gz file, but didn't work, so the device may be lost. I only have 3 more backups: boot.img, data.ext4.tar and system.ext4.tar. I guess they are useless to fix this...

Thay you for you support!