Open the upgrade tool (often EromUpgrade.exe ) and select the correct COM Port and Bits Rate (typically 115200).

[INFO] STB Model: DCT6412 [INFO] Current firmware: ver 38.1 [INFO] Upgrade available: ver 40.2 [INFO] Checking link integrity... [LINK] Server: upgrade.cableco.net (unreachable) [LINK] Fallback: multicast address 239.255.12.42 (active??)