[AT&T Samsung Galaxy S 4 Android Development] indie_dev:
This is correct; but for some reason, it sometimes won't work on my AT&T SGH-I337 phone. In fact, sometimes even using VolumeDown, does not go into the correct mode. I have to do a battery pull and do it over.

Anyway, as things currently stand

my phone is on MF3

It boots into download mode (VolumeDown + Power)

It boots into Odin recovery mode (VolumeUp + Power)

From Odin recovery, I can do a "wipe/data factory reset" without issue. It formats /data, /cache and results in "data wipe complete" without any errors

From Odin recovery, if I do a "wipe cache partition" (not sure if it's even needed after the above), it says "Erasing", then "Error"; and immediately reboots. I don't see anything on screen when it reboots; but my guess is that it is probably generating the same errors from my previous post regarding "Unknown Volume for path [/sdcard1]". Which is curious because when the phone was working, I don't recall the internal storage (my phone is the 16GB version) being /sdcard1. In fact, the external SD card (I have a 32 and 64 GB) was always seen as /sdcard, even in the Odin recovery mode when I install from external SD card - and which works just fine.

If I connect it to the PC while in download mode, Odin recognizes it, the com port etc and I can flash it with anything that's not ROM related (those tend to fail due the fw being MF3 and nothing can go on top of it at this point)

If I let it boot normally, the Samsung logo comes up, followed by the AT&T logo. Then it gets stuck. If I then connect it to the PC, the "MTP USB Device" driver (Windows 7 x64) fails to install. Which probably tells me that the phone is not in "USB debugging" mode; and I can't change that since I have no way of getting into the phone to do it and I don't know of any tool or kernel that I can flash to change it.

If I try to run ADB, the "adb devices" command fails to find the phone. Which is not surprising due to the above. And I've tried all 8 of the USB ports on the PC.

If I try to connect the phone to Kies, while at the AT&T screen, it won't recognize the phone. In fact, it says that Kies does not support the phone. Which is probably because currently, System Status (as seen in the download mode display) is set to "Custom", as per the lock symbol displayed when the phone boots up.

And when I do go into the Kies recovery process, it fails. Then I get stuck in the "update error triangle screen". Each time thereafter, when I plug the phone to the PC, Kies tries to resume the recovery. Of course it fails since Kies only has MDL and can't do anything with MF3 fw at this point. I only found this out by reading the forums. So in order to get out of this recovery loop, I use the "MF3_BTL_FIX.tar.md5" fix from my previous posting to restore the phone's state and go back to square one.

At this point, the phone is totally wiped, which would likely mean that it's no longer rooted. However, I still can't get it to boot past the AT&T logo and I think that it has something to do with the internal sdcard storage partition either being messed up, missing or having incorrect permissions.

Since I've had this phone, the only things I've done to it are:

Rooted it using the alternate method. It worked fine, the phone booted etc

Installed TitaniumBackupPro*

Backed up everything to ext SD card and to GoogleDrive

* I remember getting a problem with a frozen app and following these instructions from TitantiumBackup KB. I am not quite sure, but could any of these commands be the cause of this phone getting stuck while booting?

su
/data/data/com.keramidas.TitaniumBackup/files/busybox mount -o remount,rw /system
/data/data/com.keramidas.TitaniumBackup/files/busybox chmod 06755 /system/bin/su /system/xbin/su
/data/data/com.keramidas.TitaniumBackup/files/busybox mount -o remount,ro /system

In conclusion, I got into chat with Samsung earlier this morning. In the end, they gave me a service number, sent me an email with instructions on sending them the phone etc. Since the phone is rooted, in this state, what should I expect when they get it and should I even bother sending it to them if they are only going to send it back and telling me that I've voided my warranty?