So to put your firmware onto the phone I just do this?
Steps:
1. Put your bricked phone in bootloader mode by holding down the red power button and the down volume button at the same time until the screen pops up.
2. Open up Multiloader v5.5 and under the "control" box, select "MSM6275/MSM6280/MSM6290"
3. Plug your USB Data cable into your phone and into your computer (at this point port numbers should show up at the very bottom and the Download button should be highlighted, if not, do a "Port Search.")
4. DON'T check any of the boxes above that say, Boot Change, Full Download, etc.... Boot and Apps should be the only tabs not highlighted below.
5. Click on the "Amss" button and locate the amss_compressed_base.bin folder and then click open.
6. Click the "Rsrc1" button and locate the Rsrc_A877_ATT.rc1 file and then open.
7. Click the "Rsrc2" button and locate the Rsrc2_A877(Low).rc2 file and then open.
8. Click Download and the phone will then be reflashed. ( don't disconnect the cable until it tells you it is completed and the phone restarts.)