[Galaxy S III General] TNCS:
EFS / Baseband(modem)

It easy to criticize a member and simply tell him use the 'search function', but without realize sometimes the article will help you the most, simply just doesn't come up. Murphy's law. I was on stock 4.1.2 and after restore IMEI and EFS, the phone indicate it register on the network, but I couldn't make calls or connect to the net. This is a vary good article regarding EFS, and sadly it didn't come up easily on my search result. I came across it after I fixed the issue with tones of Googling and was searching for a different topic. But I understand people that desperate need to solve the problem quick (like I was) simply spent hour reading over hundreds of post under that article is just testing a persons sanity. So I'm going to summarised some of the stuff along with my experience. First thing you need to know:

- EFS v2 Basebands (modem) was introduced at Android 4.3 and can read EFS partition v2 and EFS v1

- EFS v1 Basebands (modem) CANNOT read EFS v2, ONLY EFS v1

If you phone is still under warranty and cannot connect to network, the best way is to stay on stock firmware and use TriangleAway to reset the flash counter and sent back to Samsung. With your IMEI number correctly showing, Samsung has absolutely no excuse on not fixing it. If you are no longer warranty, read on.

Q: My IMEI is now showing correctly but I still cannot make calls!

A: This is where the Ariza Patch kicks in. If you are on stock fimware 4.1.2, you need the Ariza Patch to fix the baseband. But after long reading over plenty post, it seems once this patch has been done, it irreversible. So beware. Before you try this patch, you may want to try update to the stock 4.3 firmware and see if it solves the problem before applying the patch.

Q: I'm on stock 4.3, now what?

A: If you still have problem connecting to the network, you need a patched modem (baseband) file. You can find them here. I think this is from the original author who did it. Instead of searching over the forums and files scatter all over the place, I'm pretty sure I dug the link out of XDA while reading through. Someone please tell me if it isn't and provide the the proper link. I'll fix it.

Q: I was on stock 4.1.2 and went to a custom 4.3 ROM, what fix shall I apply?

A: This was my scenario. And I was kind of desperate as well since I just fix my IMEI and was expect the phone to work. I wish I could come across the article on top earlier. I would've tried stock 4.3 first instead of applying the Ariza patch. Any ways, I was on stock 4.1.2 and it didn't work, so I tried a modified 4.3 TW ROM. I wish the OP would mention the EFS thing, which he didn't. I'm not blaming him or anything, but seriously not everyone keep in track of what happening with Android. The OP should mention about the EFS thing or simply post a link such as the topic above and just let people know instead of wasting hours on figuring out why it wasn't working. What I did was, after using the mod 4.3 TW ROM, the IMEI went crazy. So I thought it was corrupt again, so I ODIN back the stock 4.1.2 TW. Than I applied the Ariza patch, wolla, I could call and browse again. So I decide to give the mod 4.3 TW ROM another try. To my surprise, the IMEI still went crazy. So after more Googling only I found out because I wasn't on stock 4.3, my baseband would still 4.1.x. I tried the modem (baseband) patch which for some reason still did not work for me. So I decide to keep the stock 4.1.2 baseband and simply use a custom kernel that could read EFS v1 and v2 - Boeffla Kernel. Remember to download the 4.3 kernel not the 4.1.x! That it, you should now have a working phone.