How to Unbrick AT&T Galaxy S5 SM-G900A Soft-brick Fix & Restore to Stock Firmware Guide

This guide is intended for those who got a bricked AT&T Samsung Galaxy S5 SM-G900A, this might help you to fix and unbrick your phone and then restore it back to stock and or official firmware.





To ease your frustration on how to resolve your bricked AT&T Samsung Galaxy S5 SM-G900A that some how you ruined the right functionality of your device while you are installing a modified firmware and rooting. If your Samsung Galaxy S5 SM-G900A got bricked, then your Galaxy S5 SM-G900A device can no longer function like before it was  and this guided solution might help you especially that your AT&T Galaxy S5 SM-G900A  is now out of warranty and then spend a pocket-incinerating cost to the service center just to fix your bricked phone.


To do the unbrick, follow the simple guide. As long as you can access your AT&T Galaxy S5 SM-G900A Download Mode screen, then there’s a chance that this method of unbricking will work on your device, just be patient and give it a try. A ‘bricked’ on a device, like the Galaxy S5 SM-G900A, is caused by a corrupted firmware from your phone’s system. It won’t boot normally as what expecting. What are we going to do now is that we need to re-install the original firmware of your device by means of flashing using Odin Downloader tool, that is why we need to have the phone’s download mode access or if not this unbrick process will not help you fix your Samsung Galaxy S5 SM-G900A.

Symptoms of a bricked AT&T Galaxy S5 SM-G900A


Here are couples of issue that you might face and speculate how to do it on your own just to unbrick your device.

Soft-bricked

1. The phone boot up and shows the Samsung screen for a split second and then the device automatically turns off and even worst it will just stuck somewhere or hangs then followed by boot screen ‘Samsung’ logo.
2. The phone won’t POWER ON other than it just shows the Odin Download screen with yellow triangle and firmware update warning.
3. The phone keeps on restarting (with vibrations) after the Samsung logo appears.
– Your phone’s capacity to function well can be recovered if you can still access your Samsung Galaxy S5 SM-G900A Download Mode screen - (Pressing VOLUME Down + HOME + POWER button, then Volume up).
Try to press that button on the given combination. If you can access the download mode option, then you’re apparently somewhat lucky. If this won’t work as designed then you are in big trouble in dealing with your bricked device. If this will work, there is a big chance that you can recover it by yourself.

Hard-bricked


It refers to the phone as totally wedged, unresponsive or no visible signs of turning ON and somewhat not giving you the chance to breath knowing that you may avoided the worst of it, (paying the technician on his remarkable job). It doesn’t show anything like you are in a black hole and you can’t access the download mode screen. The only way out for this is by performing the next step. The sharp technicians called it JTAG flashing. To do this is by forcing to install the firmware back to the phone. The process is not too easy especially at first hand you don’t have enough know-how on this process. This includes disassembling the phone with some soldering required and flashing by means of using a flashing device tool.

Performing this method means that you cannot save your device all by yourself anymore. If you considered necessary to have your Samsung Galaxy S5 back to its performance level, the best way to do now is to bring your device back to your dealer. Give explanation that might encourage them to have your Samsung Galaxy Note 3 fix for free or have an exchange for warranty.

How to Fix Bricked AT&T Galaxy S5 SM-G900A Flashing with original firmware or stock ROM


Grab Odin flasher and USB driver
  • Odin flasher – Odin3_v3.09
  • Grab USB Driver - USB Driver or install  Kies 3
  • Download AT&T's Galaxy S5 SM-G900A original stock firmware from this page.
  • Choose the stock 4.4.2 G900AUCU2ANCE as there are no available stock firmware like the recent OTA update G900AUCU2AND3 and so on.
  • Extract the downloaded files and you may likely use  winzip, winrar 7zip or any extracting tool for a compressed files.
  • Please use Windows OS PC or laptop as this method will not work on Mac.
  • Recharge your battery using external battery charger since you can’t recharge it within the phone for it is already bricked.

Step 1.  Run Odin on your computer.
Step 2. Reboot your Galaxy S5 SM-G900A into download mode screen.
Turn it off, once completely shut down hold down the ‘HOME’ + ‘VOLUME DOWN’ buttons and press the ‘POWER’ button for about 2 seconds until a WARNING! Screen appears. Press the ‘VOLUME UP’ button to continue or enter Download Mode.
Step 3. Connect your Galaxy S5 SM-G900A phone to PC using the supplied USB data cable. Then make sure you can see the phone “Added” in Odin log-cat or a  COM:ID  turns into bluish color once the device is being connected.
Step 4. In Odin options, DO NOT tick ‘RE-Partition’ ONLY Tick ‘Auto Reboot’ and ‘Factory Reset Time’ and nothing else.

Step 5a. Flash the AP file Only without losing user data
If you have some important data that are still on your Galaxy S5 memory then you may only use the single file AP binary file, then proceed below and do the backup later once your phone has returned to boot normally. This process will downgrade your Galaxy S5 phone to the old 4.4.2 firmware G900AUCU2ANCE but at-least you can start from scratch again. One disadvantage of flashing only AP_G900AUCU1ANCE binary file is that you cannot update to the official OTA update, but you can simply fix that by flashing the other files such as the CSC_G900AUCU1ANCE and the CP_G900AUCU1ANCE.
Now simply click the AP button and load the AP binary file. It simply should looks like this screenshot.


"AP_G900AUCU1ANCE_964333_REV00_user_low_ship_MULTI_CERT.tar.md5"
Step 5b. Flash the Full stock firmware without the Bootloader Image
Flashing the full stock firmware has an advantage as it will restore your phone to a fully functional as it can receive OTA update again. If you need to re-root again later then this is also highly recommended.  This process will delete all stored data from your phone as we are going to flash the full factory images such as the AP_G900AUCU1ANCE , the CSC_G900AUCU1ANCE and the CP_G900AUCU1ANCE, minus the booloader image which cannot be done due to the phone's security restriction.



Step 6. Click on “Start” to flash the stock firmware.


Step 7. Wait ’till it finishes flashing it's likely you'll see a huge message that says "PASS!"
.

If the phone will then reboot to its normal mode then it’s your lucky day. If the bricked symptoms still persists, refer to the below method. Don’t lose hope we are not finish yet.

If somehow you'll see a message that says "FAILED",  just take your time and repeat the whole procedures from top to bottom.


Try to recheck everything, including the USB data cable, the computer USB port, and the USB driver., It's only in-between of these troubles causing the flashing failure.

If the phone reboot normally, it’s then a success story. You may then perform factory reset if necessary, this resolves issues for unwanted boot loop, stuck on welcome screen logo. Here's how to do it.

- Turn off the phone and set it into recovery mode
- Press volume “volume up, home and power buttons”
- Once in recovery mode, perform full wipe
- Select ‘wipe data/factory reset’

Restore AT&T APN Settings on Galaxy S5 SM-G900A


It is also highly advised that once you flashed back your phone with the stock firmware your APNs will probably get wiped and it troubles you while connecting to data network, so simply re-enter them manually. To do this, simply go to settings, then wireless & networks, then mobile networks, then access point names, and then press menu and add new. This will give you a list to enter in all your APN settings for AT&T.

Name: ATT Phone (Some might have PTA in place of Phone)
APN: phone
Proxy: Not set
Port : Not set
User name: Not set
Password: Not set
Server: Not set
MMSC: http://mmsc.mobile(dot)att(dot)net
MMS proxy: proxy.mobile.att.net
MMS port: 80
MCC: 310
MNC: 410
Authentication type: None
APN type: default,mms,supl,hipri,fota
APN protocol: IPv4
APN roaming protocol: IPv4
Enable/disable APN: APN enabled
Bearer: Unspecified

If the problem of your device still exists, then at this point there is nothing we can do or add more but giving you a recommendation that you have to contact or visit your nearest service center to get it fix. By the way, I can guide you about JTAG, but it requires a heck of tearing down the phone completely, a JTAG flashing toolkit and soldering skills. So, I guess it’s not applicable to share to everybody. It’s a technician job already.

So, congratulations to those who successfully fixed their bricked AT&T Galaxy S5 SM-G900A by this method, and to those who did not make their device work at this moment, don’t lose hope. Try your luck again. Next time, be careful while modifying your precious AT&T Galaxy S5 SM-G900A. No one could stop you from unbricking your device, but extra safety measure is much better safe than sorry.
Edit