[T-Mobile, Samsung Galaxy SIII] flipster64:
I got it from amazon as a refurb. It looks shiny and new. Had a rooted, modded 4.1.2 version of android with some T-Mobile branding (boot picture, for instance) I don't think it had CWM on it, but it might have been -- I wasn't looking for it at the time. I flashed a version of it with Odin, but I can't say for sure what was there to begin with. But it's been a long trail - regardless, I ended up flashing a version of CWM on it (like a 6.1-ish version, then was advised to update it, so I went to Philz 6.07.9)

The story so far ...

I got the phone. It worked fine, except for the fact it didn't have WiFi calling, which I use quite a bit due to my house and my sons' houses not getting great reception. That's when I decided to try finding the WiFi calling app. I tried Kies sofware update, but it said both that it was up to date, and that Kies couldn't update the phone (but I think that's when I tried the latest version which supposedly doesn't work with this "older" phone (before ... what, Sept 2013?). Even tried exporting the app from my HTC and importing it to the Samsung, but the app just crashed when I tried to load it.

I did note that in download mode it said SGH-i747, but I didn't think too much of it (yes, it bugged me a little) because I know manufactuers of electronic equipment often use each others' chips and I had even read that these two models were practically identical ... and may even BE identical exept for the firmware (it would be cheaper for Samsung to manufacture the same thing and cheaper for T-Mobile to purchase an already mass-produced product and just flash it with different firmware - plus Qualcomm's virtual modem software makes this easier to do). So I went to upgrade it to root66 T-Mobile 4.3, after having a conversation here that the root66 4.3 mod was deknoxed and it definitely has wifi calling (it does, too).

It said to flash a particular modem first, so I did the modem, then [nope! the 4.3 root66 rom] a deknoxed rooted stockmod 4.3 mod in a zip file, and it rebooted.and upgraded and came up as a really nice mini android PDA ... that is, it had no phone network. We looked into it and the IMEI had been wiped.

So I got instructoins from WhoWhere on how to re-generate and write the IMEI back to the phone, but it uses RMNET, and RMNET drivers load and then crash on the three .... actually 4 different computers I tried it on (two Windows 7 boxes, a Windows 8 netbook, and even an old XP laptop that had never seen a phone, kies, or any other phone software. Same thing happened on all four.

At that point I thought hey, maybe there's something to this i747 thing. But first I (and WhoWhere) thought I'd restore a 4.1.2 backup to see if the IMEI was really lost, and to see if RMNET from the backup (if it indeed gets backed up, I'm not sure) would work and I could re-write the IMEI there. (Subsequently through various searches with better chosen words, I see that this cross-modding on i747/T999 is not that uncommon.)

So, yes it was gone, and no the drivers still crashed.

So I wiped/reset and flashed a stock mod base 4.1.2 TMobile image to see if that would help. It didn't. Tried different modems. They didn't help.

That's when I posted another simple questoin asking if it was normal for an SGH-T999 to come up as an SGH-I747 in download mode. Which is how I got Perseus71 involved ... who has been very patient and helpful, by the way. Yes, it's currently bricked, but I went into it with my eyes open and I knew this was a risk I was running and it could happen any time.

I should insert here that I worked at a University Computing HelpDesk for 7 years, I know how difficult sofware/hardware support is over the phone and over email when you can't see what the other person is actually doing. So I know a little bit about what he's going through. I'm a 30+ year IT Pro and have been a sysadmin for our University's email servers - currently our Windows based Cognos servers and linux based Informatica servers. CS degree -- all that. Not trying to toot my horn or anything, I'm no super-whiz, just giving you a bit of background on where I'm coming from. Until a couple of weeks ago, I knew very little about Android, though. I had followed instructions and rooted my Nook Tablet, then built a custom bootable SD to boot into Cyanogen Mod 7. I digress but I think it's worth mentioning.

Back to the story... Perseus and I have been going back and forth narrowing it down to the fact that it does, in fact, have an I747 bootloader, even though it says it's a model SGH-T999. Full ROMS won't flash with Odin, though CWM will. I flashed that TMO 4.1.2 stockmod with CWM which didn't help, so we both decided that the tmo_UVDMD5 firmware update was the way to go to replace the bootloader -- but it kept failing on a security check in the first line looking to make sure it was a d2tmo (which in some places it reports it is, including that device info app I downloaded. The GetProp app I downloaded just crashed when I tried to run it). So feeling pretty certain of it, I removed the security check in the script for the firmware update, and it hard bricked.

On whether or not it's an i747 motherboard ... here are my thoughts for discussion and comment.

What are the chances that a phone with an i747 motherboard would be in a body with a T999 sticker and a T-Mobile back, with a T-Mobile logo at boot time? I'll grant you maybe not zero, but I'm using Ocam's razor here.

What are the chances that somebody bought an SGH-T999 and was playing around with modding it, didn't like where he was getting ... had flashed an i747 bootloader on it, got it working with a T-Mobile modded ROM, and then returned the phone? Then the refurb people booted it up, it worked, so they put a new back on it and maybe a new screen and sold it as a refurb?

I'm thinking the chances of that are a lot greater. I know, I could be wrong. I can always be wrong. But that's the way I'm leaning.

Then the next quesiton is, if this recovery thing works (I'll run out at noon today and get a class 10 16gb MicroSd and flash a T999 image on it and see if it boots into safe mode) ... I suppose the smart thing to do at that point would be to recover it to last good state, which is the funky state it was in before I flashed the T999 firmware -- then boot it up "normally" and re-assess where to go from there.

All contingent on how the sd card thing goes.