[HOW TO] Flashing your ZT280 C91


Oct 20, 2011

Here's something else from the French forum I mentioned in my topic on Rooting the C91 - *Update* I already tried this method and installed the ICS on my tablet! - by the way I installed the xxx2n version(http://www.zenithink.com/Eproducts_C91.php?download ;if you are not sure which version to install because your Model num doesn't have a xxx2n or xxx3n then use the file browser to go to your internal memory - there is a text file which has 2n in its name (my tablet was the xxx2n version - I don't know for 3n version users, just see if you have such a file in the internal mem) ) :

That method is not originally mine - I'm just translating what I found in this post -
TabletteDroid.com Le Forum ! • Afficher le sujet - METHODE POUR FLASHER UNE ROM ZT-280 C91
so all credits should go to the person who originally posted it.

Method for flashing a ROM for the Zenithink C91:

ATTENTION (yup that's pretty much a copy/paste from the topic on Rooting):
There are risks involved in the flashing of your device.
If you do something wrong, or use a corrupted(badly-decompressed) ROM (no idea what they mean by badly-decompressed - guessed it should be corrupted) or if your tablet shutdowns during the flashing due to lack of energy, etc. (there are a lot of things that could happen) that could lead to the "death" (I mean it may not work anymore) of your tablet. Nor the forum (
http://forum.tablettedroid.com; I'd add also http://www.androidtablets.net) , nor the person who wrote this (cake1974;nor me, I'd add) will be taken responsible for any damage caused to your tablet by flashing it.

1.Format the microSD to FAT32.
2.Shutdown your ZT-280 C91 and start charging it.
3. Create a folder - " zt-update " on your MicroSD.
4.Copy the files from the ROM to the " zt-update " folder
5.Insert the microSD in your ZT-280 C91
6.Turn on your ZT-280 C91 and immediately click on the camera button
7.Click again on the camera button to confirm (there was no need for this when I installed the ICS on my C91)

List of files to copy to " zt-update ":
The file "license1.ef" is a Dolby Digital license.
It is necessary for AC3/DTS audio decoding.
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If you have any questions feel free to ask.
Last edited:


Mar 17, 2012
Thanks for this input , it is nice of you.

i am looking to downgrade my C91 from 4.0 to 2.3.
help with instruction will be great.


Oct 20, 2011
Here's firmware to download:
You just have to choose the correct 2.3 version and flash it - btw there are some good 2.3 custom versions, so you might want to check them out.