Finally some one who answers all questions and above all, as complete as possible. Not all users in trouble do so making it difficult to determine the problems as exactly as possible.
So you have all things twice, device and igo?
On the faulty device, something has gone wrong, either a software (corrupted file)or hardware issue (damaged memory bit or byte).
Since igo is very easy to install again (copy/paste) I suggest to delete the whole faulty igo and replace everything. When the igo on the two devices is different after all, it may be useful to back up the old program and restore the files you want (sys.txt, skin, ..). I hope this method overrides the faulty (hardware) byte when there is one. It sure will correct all software issues.