Download Mode?

1. The easiest/most common method

• Turn off your phone

• Plug USB into computer

• Hold Vol+ (Vol up) AND Vol- (Vol down) at the same time

• Plug USB into phone while still holding both Vol's

• If a Yellow Triangle with Andy shoveling pops up, then congratz! You're in download mode now.

 2.   Didn't work? Try this one:

• Power phone off

• Plug USB into Computer

• Plug microUSB into phone

• Hold pwr + vol up + vol down

• When Battery icon goes away, release pwr, still holding vol up + vol down

• Yellow triangle, Downloading, Andy shoveling, Do not turn off Target!!! symbol) 

• You should now be in Download mode.

THIRD METHOD

• Power phone off

• Pull battery out

• Hold vol up + vol down

• While holding vol up + vol down, plug in USB cable into the phone 

• While still holding vol up + vol down, put battery back in 

• Yellow /_\ (triangle, Downloading, Andy shoveling, Do not turn off Target!!! symbol)

• You should now be in Download mode.

FOURTH METHOD (adb)

• Enable debugging on your phone (Menu>Settings>Applications>Development>)

• With phone on, plug USB into computer and phone 

• Open cmd

• Type in "adb devices" (not totally necessary, but I always do it just to make sure everything is good), making sure it recognizes your device

• Type in "adb reboot download"

• Yellow /_\ (triangle, Downloading, Andy shoveling, Do not turn off Target!!! symbol)

• You should now be in Download mode.

Soft brick on Samsung Galaxy S4G from T-Mobile

Hey there, I'll share this lesson I just learned recently.
I have the Samsung Galaxy S 4G from T-Mobile and I was getting a little frustrated because when I was trying to download the apps that I like, I ran into the same problem:

This app is not available for your device.

 UGH. So I looked for some information on how to fix that and I read something about updating the firmware, that of course led me to ODIN...  (I'll explain that in another post) ... But somehow, something went wrong, I THINK it's because I was following the instructions of a regular S4's firmware. So I ended up with this screen:

                                PHONE, EXCLAMATION MARK, COMPUTER. WAIT WHAT.

I tried to turn off the phone, it didn't work... I tried to get it into download mode. Didn't work either.
Tried to follow instructions on the internet. Didn't work either because they were all for the standard version of S4, not the T-Mobile one...
SO
If, by any chance, you have this same problem, what I suggest you to do is:

1. DON'T panic. It's not bricked.
2. Get the stock rom for your device. Here's a Gingerbread one: http://droidangel.blogspot.com/2011/11/t959vuvkj6-t-mobile-usa-samsung-galaxy.html
3. Extract the file. It should be named as T959VUVKJ6-REV00-home-low-CL694130.tar.md5
4. Download Odin to your computer
5. Connect the phone via usb to your computer while it is at the recovery/download screen
6. Place the stock rom file into the section marked PDA in odin and flash to the device.