"Failed to run firmware upgrade. Unknown error occurred."
Happened to me three times when I used Kies. First time was with the previous update of 2.3.6. Actually, first two time. Third time was when I tried to update to ICS, last night, again using Kies.
If you continue to get this error message after removing the battery and powering back up, then don't freak out. I was able to fix mine, and I'm sure you can fix yours, too. This is what I had to do to get the previous firmware and the current ICS version installed on my SGS2:
1) Go to sammobile.com and register as a user. That way, you'll be able to download firmware. sammobile.com is a third party outfit that gets all the official firmwares for all the Samsung devices. They get these almost immediately after Samsung releases the firmware. The link for the last 10 updates for the T-Mobile USA version of the SGS2 is http://www.sammobile.com/firmware/?page=3&t=1&o=1&m=SGH-T989&r=-1#modelsa Again, you'll need to register as a user to download any firmware, and you're only allowed one download every 30 minutes unless you become a premium member. (I don't work for this outfit, and I'm not trying to advertise anything, here. This was the only place I was able to find the firmware outside of Kies.)
2.) Do a Google search for ODIN3 software. Current version is 1.85. Get it, download it, and install it on your PC. You'll still need Kies installed to ensure that you have the proper drivers installed on your PC. ODIN is a software package that developers use. It works like a charm. At least, it did for me all three times....provided you follow instructions to a "T".
3) Once you have the ICS firware downloaded (UVLE1), unzip it to a folder on your PC. There will be a couple of files. One is an .DLL file (SS_DL.dll). Just ignore that. It won't be used. The main file is a .tar file (actually, it's a .tar.MD5 file extension). This is the one that will get used. The original zip file is huge (410 MB), and it will take a while to download and to unzip.
4.) Once ODIN3 is installed and the zip file is unzipped, open ODIN3 and connect your mini-USB cable to the PC. There should be a couple of boxes already checked in ODIN3: The "Auto-Reboot" box and the "F. Reset Time" box. Leave these boxes checked. Next, check the "PDA" checkbox (small box to the left of PDA). Finally, click on PDA. It's a button that results in a pop-up window. Locate the unzipped .tar filie that is the ICS firmware and click on it. The file name will appear in the long rectangular box to the right of PDA. You are now set to connect your phone to the PC.
5.) Turn the phone off, remove the battery, and re-install the battery. Do not turn the phone back on. Leave it off while doing this step. Although you get the error message on your phone, you can still put it in the download mode. The way to do this for the T-Mobile SGS2 is to hold BOTH the Volume Up and Down button at the same time with one hand while you connect the mini-USB cable with the other hand. Just put your finger in the middle of the switch to push both down at the same time. This is a rocker switch, and you'll be able to do this with that type switch. Hold the VOLUME UP and DOWN switch down while connecting the USB cable. DON'T LET GO OF THE SWITCH UNTIL YOU FEEL A VIBRATION. Usually takes a few seconds. If you're successful, you'll see a see a warning screen about installing new firmware. Also, you'll see the "ID/COM" box in ODIN3 turn yellow. This is good. It means you're in the download mode and properly connected to the PC. Next, push the Volume Up button to go into the download mode. The original error message you got will reappear (if it wouldn't go away to begin with). You won't get the error message if the phone was able to return to it's normal state after attempting to use Kies to install the firmware. Instead, when you click the Volume Up buttone, you'll see the "Download" message on the phone. Either way, you are now ready to download the firmware to the phone.
6) Click the "START" button in ODIN3. You'll see some activity in the top left box of ODIN3. You'll also see some text appear in the Message box. This is normal. The firmware is now downloading. You can lay the phone down while all this happening. It will take probably 5+ minutes for all the firmware to download.
7.) Once downloaded, you'll see "PASS" appear in the top left box in ODIN3. The box below it will have green bars appear one by one until it's full (after successful download). Additionally, you'll see a message appear on your phone and then you'll see your phone reboot. Just leave it alone until you see your phone reboot like it would normally. Once that happens, you can disconnect the cable. This should be the end of it.
I'm fairly sure I have it all there. If someone disagrees, feel free to correct me or add to this. Also, I'd confirm what I said here on Google. You can do this by searching out how to download firmware and using ODIN. I assume no responsiblity for what I've said here. If you really do brick your phone after this, then I won't be responsible. However, I had no prior experience doing this and I was successful doing it three times.
Good luck and let me know how it goes.
Message was edited by: mlbinseattle