I haven't got much experience with the RKBatchTool so I don't quite know what the error message means seems like some kind of check failed (duuh).
It shouldn't be a hardware problem as other FWs seem to flash just fine so whats left is the 3.4.2 firmware package itself;
- If you haven't yet tried to re-download the image, the file you are trying to flash might have been corrupted while downloading.
(you might be able to check the file's integrity by checking against a MD5 or SHA checksum but i don't know if GPD has supplied any)
- If you do have tried to download the file multiple times and none of the downloaded versions flash without errors, The firmware file itself
might be broken. This just happened to me with a Nexus 7 this week where google supplied a broken bootloader with a certain firmware
also after a short google search i found this thread about someone with similar problems:http://boards.dingoonity.org/gpd-android-devices/gpd-xd-update-3-3-7-to-4-4-2-bricked/
He seemed to have downloaded the FW image from this thread:http://boards.dingoonity.org/gpd-android-devices/the-latest-firmware-of-gpd-game-console/
If you are going to Mirror them on your site I suggest to zip or rar or tar.gz the images before uploading them.
This way you can ensure that people won't brick their system if the try to flash an Image that was corrupted while being downloaded.
(they wont be able to extract a corrupted compressed file)
I flashed 3.4.2 successfully a year ago or so I gonna search my PC later, maybe I still have the image.UPDATE:
haven't found it sorry.
It was probably on my Windows partition which I got rid of since I completely switched to Linux.
I probably got it from the thread with the ( now ) dead links.