I was running into the same/similar error. Inside of /var/lib/dpkg/updates one of the files appeared to be stopping my update process. The contents of the file was,
#padding
#padding
#padding
#padding
#padding
repeating for 150 something lines.
I moved that file out of /var/lib/dpkg/updates and everything seems to be working fine afterwards. Whether this was the root cause or not I am not sure, but it might be worth while grep(ing) for this in all the files in /var/lib/dpkg/updates.
I was running into the same/similar error. Inside of /var/lib/ dpkg/updates one of the files appeared to be stopping my update process. The contents of the file was,
#padding
#padding
#padding
#padding
#padding
repeating for 150 something lines.
I moved that file out of /var/lib/ dpkg/updates and everything seems to be working fine afterwards. Whether this was the root cause or not I am not sure, but it might be worth while grep(ing) for this in all the files in /var/lib/ dpkg/updates.