Thanks for the quick reply!
 So it looks like $50 for a programmer and chip, only to not know for sure if it will be fixed for good, or for how long. I love the unit, but I think the MPX-1 will have to do for right now.

Yeah, the ROM checksum failing certainly points at the flash chip. It might be a simple matter of burning a new chip.  There is information on the chip here: http://www.stecrecords.com/smf/index.php?topic=740.msg1002#msg1002.

If the checksum is failing it's impossible to know how the device will behave. It's a lot like having bad sectors on your hard disk; apps using the space might work ok but could fail in unexpected and destructive ways. Like blowing out your speakers.

Some of the other causes for E1 are much worse however so this unit might be salvageable. 

Hi everyone, I have just bought a used G2 from a large retailer, and it is giving me an E1 error on startup. I opened her up and see no obvious signs of damage except one leg of the battery is snapped off (which I have temporarily fixed).

The facts:
Unit starts, flashes just 1, brightly, then adds an E in front of that, and the brightness slightly dims.
If I tap then hold the "program" button (or something similar, sometimes 6-7 taps) the unit will reset and work how I would consider normally. I have plugged into my guitar amp and it passes audio, and all effects function as I would expect them to, albeit a little noisy.

I have just entered diagnostics mode by holding edit while tapping and holding program to skip over the error, and am running the various tests available.
I have read this thread (http://www.stecrecords.com/smf/index.php?topic=822.0) multiple times, and I have reseated the firmware chip. My answers to Bob's questions are:
1: the unit functions normally after clicking and holding "program," all LEDs and LCDs work.
2: after the error is displayed, it will function normally after clicking and holding "program," all audio works as expected
3: It fails every time, even after I have recommend the battery.

Thanks in advance for any help! I have twenty something days to return this if it is defective, so I am trying to figure out any possible solutions quickly.

PS, I am handy with a soldering iron, but my only diagnostics tool is a multimeter.

Update:
I have run all tests
All passed except the ROM checksum and the footpedal. The footpedal is expected as I have none connected, but I am guessing my ROM checksum failure is related to the E1. I appreciate any ideas or insight into where to go from here to fix it, or should I cut my losses and return it?

PPS. It is also worth noting that the program button trick to escape the error only works sometimes. Other times it results in the unit rebooting and going back to square one, or just changing the number under MIDI from "1" to "2", and making the E disappear