reTerminal DM sudo apt upgrade fails

I’ve purchased reTerminalDM and I’m performing the initial setup. When I execute “sudo apt update” and “sudo apt upgrade,” I receive a message stating that /var/lib/dpkg is read-only, preventing installation.

  1. I’ve attempted to allow writing to /var/lib/dpkg by using the mount command with the -o rw option, but this also results in a failure message.

  2. I’ve checked the sectors using the badblocks command, but found no issues.

  3. I’ve tried granting permissions using the chmod command with the 777 option, but this also results in a failure message.

  4. Upon shutdown, I receive a message stating that “/var failed to unmount.”

Do you have any advice or solutions for this issue?