dev-zzo
repository of ZynOS firmware
Not really an issue, but if you are still looking for other ZynOS firmware to get back to testing your code after all these years, have a look at: ftp://ftp.zyxel.lv and ftp://ftp.zyxel.com.tr
binwalk extracts the file system in only about 20% of them. I'll start playing with your code shortly to see if I can get to more FS.
No surprise; the variety of image formats is staggering even within one single manufacturer's product lines. Binwalk is a great quick inspection tool but fails quickly against more elaborate formats.
I'm gently mirroring both sites for myself, maybe I'll have a look when I happen to have free time... if you have an interest in a specific device, feel free to let me know.
Not really interested in any specific model. (Although I'm keen on solving the PK5000Z) I'm just casting a wide net to understand the various keygen algos that zyxel has used, see link below. https://forum.hashkiller.io/index.php?threads/unpublished-wpa-key-algorithms.19944/page-17
Completed the PK5000z keygen! Thanks a bunch of developing your router-tools. And gave you a shoot out on the hashkiller forum... Perhaps talk to the unblob devs to get your code integrated into their binwalk alternative.