The EasyBox 804 is almost always locked to a specific ISP. Consequently, there isn't a single universal firmware version. Vodafone-branded units run a modified version compared to a unit from Unitymedia or a generic retail Arcadyan device.

Avoid shady "firmware download" websites. Unofficial firmware can brick your router. The Easybox 804 does not support OpenWrt or DD-WRT, so flashing custom firmware is impossible without advanced hardware modification (JTAG).

: The web interface provides basic troubleshooting, including connection status and device logs accessible via easy.box in a web browser. Administrative & Maintenance Options

Technically, yes. Practically, not recommended. Most ISPs disable firmware downgrades to prevent security vulnerabilities. If you attempt to flash an older version, the bootloader will reject it with a "Version check failed" error.