User manual ZyXEL P-2812HNU-F1 (English - 422 pages)
Reset Zyxel P-2812HNU-F1 OpenWRT Using Serial Console Access - YouTube
FS#2226 - zyxel P-2812HNU-F1 initramfs has been broken with LZMA: uncompress or overwrite error 7 since R47026 · Issue #7081 · openwrt/openwrt · GitHub