Puuh, zip is not = zip !??
I tried that on two cheap "China" Navis, one NozaTec (WinCE 6.0) and a Hieha (Android):

I simply wanted to change some wrong translated phrases in Info.ini of a xxxTTS_Voice.zip (content/voice). But as soon as I restart iGO it stops loading after a view seconds (exceptional error...). Copying back the org xxxTTS_Voice.zip iGO starting normal again.

Even if I just let 7zip in Windows unpack and repack the xxxTTS_Voice.zip containing exactly the same (visible?) folders and files without any change it is now corrupted somehow..
There must be more in a xxxTTS_Voice.zip but only zip, may be some hidden manifest etc..pp ??

What am I doing wrong?