Also, you will have to change parameters in sys.txt related to resolution.
But, keep in mind that there are also versions of exe that do not work with different resolutions. You didn't say what do you have. It is easier to download whole dedicated package, and also change parameters in sys.txt:
Links from posts #4/5/7 and #8 are OK and they work fine.
If you insist on ordinary iGO8, ok. But, I guess that now you have modern device, and recommendation is to
install Primo 2.4. Why don't you try?