detonator

Yes, it's original VMG8623-T50B from Vodafone. I've found another page referencing old firmware https://www.techforum.cz/topic/61871-internet/ .

Hi, on this page (https://www.vodafone.cz/pece/internet-data/internet-dsl-optical/modem-zyxel-vmg8623-t50b/) is link to download latest firmware of VMG8623-T50B but the file with firmware is broken, modem is refusing to update. On English version of that page is link to very old firmware from 2021. Please Vodafone, upload correct firmware binnaries (to all language versions) and check they are really working!