avrdude: stk500_getsync(): not in sync: resp=0xd7

I've got a Solidoodle [Sanguino - ATmega644P] and I've recently installed a new E3D hotend. I need to update the max temp but I can't for life of me, this entire day I've worked on it, actually upload firmware. I always end up with "avrdude: stk500_getsync(): not in sync: resp=0xd7"
I've installed every single driver I could ever find.
I've hit the reset button before, during, and after.
I've unplugged all plugs [except stepper drivers, but I didn't have that problem when uploading to my Megatronics with step drivers installed]
I've tried many, many different hardware patch iterations for Arduino IDE
I've tried a few different Arduino IDE's [0022, 0023, latest 1.05-r2]
I've tried several different firmwares, many Marlin's, original, Lawsy's, Lawsy's later, plain Marlin, and I've tried Repetier
I've also tried countless combinations of everything above.
I'm at a complete loss.
Unless it doesn't compile right [a pin not defined, usually] I always get the error "avrdude: stk500_getsync(): not in sync: resp=0xd7" with the last two different here and there.
Every site I look at that has fixes for these errors has not worked for me. Hopefully I was thorough enough that you won't throw answers I've already tried at me, including turning it off and turning it on.

avrdude: stk500_getsync() is a communications error. It cant talk to the bootloader... maybe wrong baud rate (in boards.txt) or even no bootloader installed.
Or just an issue with the auto reset (needs to be enabled and working, as boot loader only runs for 3 seconds after a reboot)

Different firmwares will not help, as long as they compile they should work. (as long as you have the correct board type defined)

So check you have auto reset enabled (normaly a jumper)
try a few baudrates in the boards.txt file for the Sanguino chip (normally 38400 or 57600) (reload Arduino after you edit these file to reload them)

If that fails get yourself a avr programmer, put your own boot loader on it. or even upload directly without a boot loader.

Edited 1 time(s). Last edit at 05/03/2014 12:20AM by Dust.

I'd rather just buy a new mobo than buy something to rig my older one. heck, maybe I'll grab another Megatronics V3. After getting that working it was wonderful. Getting it working was a journey going between those in the know and Repetier and learning EEPROM trap the hard way, etc.

If its a real 644p in a 40pin dip, you can get one of those preprogrammed and just replace yours.

eg [www.emakershop.com] or [www.emakershop.com] etc (1284p is drop in replacement, with more ram and rom, better for marln)

and a avr programmer is a tool... anyone working with AVR chips should have one.

Changing baud rates resulted in
"avrdude: Yikes! Invalid device signature.
Double check connections and try again, or use -F to override
this check."