(Soft) bricked phone?

[Chezzykun]

Hi all! I recently bought a new motherboard on ebay for my T-Mobile Samsung Galaxy S3 [SGH-T999] because my old one stopped working. Once I received the motherboard I first noted that it was SGH-T999L (the one with LTE). However, besides the difference, I replaced it with my old nonworking one and it worked, except my wifi wasn't working. So I asked my friend who's much better at phones than I am, what I should do, and he told me to wipe the phone and flash a custom firmware / rom with Odin, so I did. That didn't work (for some reason, it gave me an authentication error), so he then told me to flash a kernel? I did that, and that passed, so now I try to flash a firmware but it doesn't work. It gives me an error like so:

<ID:0/005> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> T999LUVUBNF4_T999LTMBBNF4_T999LUVUBNF4_HOME.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/005> Odin v.3 engine (ID:5)..
<ID:0/005> File analysis..
<ID:0/005> SetupConnection..
<ID:0/005> Initialzation..
<ID:0/005> Get PIT for mapping..
<ID:0/005> Firmware update start..
<ID:0/005> sbl2.mbn
<ID:0/005> NAND Write Start!! 
<ID:0/005> FAIL! (Auth)
<OSM> All threads completed. (succeed 0 / failed 1)

On the download mode screen it shows (ignore the really high triangle counter, it was at 18 when I receivd it):

ODIN MODE
PRODUCT NAME: SGH-T999
CUSTOM BINARY DOWNLOAD: Yes (20 counts)
CURRENT BINARY: Custom
SYSTEM STATUS: Custom
QUALCOMM SECUREBOOT: ENABLE
Warranty Bit: 1
BOOTLOADER RP SWREV: 1
SECURE CHECK FAIL : sbl2

I am able to boot into custom recovery (twrp) and download mode, but when I try to boot into system, I get the bootloader, and nothing after that.

(Also when I plug my phone into my computer there are no folders in the phone besides TWRP).

What should I do? I just want a working phone again. :c

 

[GSDer]

Hello and welcome to the forums!

Sounds like you should start out by loading this firmware and see if it completes successfully.

Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM -0.001 using Tapatalk

 

[Chezzykun]

It didn't work. It gave me the same error. ):

 

[GSDer]

Sorry, this is beyond me. You'll have to look for a JTAG service and see if they can force the correct firmware on it.

Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM -0.001 using Tapatalk