I think, is need compile new .bin firmware with bootloader from original o2 firmware, correct?
1/ Can someone please help me with this?
I want to update the router with the latest openwrt if possible
2/ Alternatively, while you're at it, can you check what the login and password (in filesystem) are for the serial console (putty-uart) if enabled?
I wanted to connect via console to be able to control the modem via AT commands, but of course the console has an operator password that I don't know (After unpacking the binary, the MD5 hash of the password should be accessible)