Okay, I
finally managed to get the new firmware file (75 Mbytes) downloaded from the Jinke site, using a "download manager" (doing it straight from the browser never made it past about 6 Mbytes, due to the extremely slow connection). After installing it on my PEZ, there were only three differences from the most recent Astak firmware release (when looking at the Settings/About screen).
V5_2009_09_10_ASTAK:
Firmware version: V2.02ASTAK.090907
PDF parser version V2.00.090907
BookShelf version: V2.00.090907
V5_2009_10_15_JINKE:
Firmware version: V2.02EN.091015
PDF parser version V9.00.090915
BookShelf version: V2.00.091015
No clue WHAT the changes are, but obviously they're limited to the PDF viewer and the 'BookShelf', which I assume is the menu/folder-viewing directory software.