Bad Bios Flash On Xbox 1.1 With Xecuter 2 Options

[ib_desperate]

In desperate need of help although all might be lost!!

I have an xbox 1.1 with an Xecuter 2 modchip.
I don't know any of the details as I purchased it modded a long long time ago.
The original hard drive was swapped out ages ago for a 120GB

I was trying to swap out the hard drive again and put in a 200GB one.
I tried to flash the bios so that it would detect more than 137GB
I must have used the wrong bios as it all went pear-shapped

It now attempts to boot 3 times and I then get flashing lights (christmas trees?)
The mod chip has an external switch, and when I turn it off - the boot process gets futher but then fails as I suspect the original microsoft dashboard isn't in the correct place on the hard drive.

Have I any options to fix the bios on the modchip?

I have another soft moded xbox if it helps, but I'm no good at soldering so moving the current mod chips isn't an option.

I believe as the box is a 1.1 - even if I manage to soft mod my current chipped xbox - I couldn't use it to reflash the modchip bios?

Any suggestions to move forward would be greatly appreciated..