I've found this useful command in the /bin/kobo_config.sh:
Code:
ntx_hwconfig -s -p /dev/mmcblk0 PCB 2>/dev/null
On my Kobo Glo HD this script prints 'E60Q90'.
The another useful info is inside the folder /upgrade/mx6sl-ntx/ of each kobo-update-x.y.zzzz zip file.