The absolute safest place to get firmware is from the manufacturer's official website. For FNIRSI, that is and https://www.fnirsi.com .
Disconnect, power cycle the device, and re-enter boot mode precisely. Corrupted firmware or cache mismatch. dsotc2 firmware link
Always source your installation files directly from the manufacturer to avoid bricking your unit with corrupt or malicious files. The absolute safest place to get firmware is