I suspect this is because you have configured your sources.list file to communicate via ftp.
2020-09-08 20:07:42,661 DEBUG Checking pkg: ubuntu-standard 2020-09-08 20:07:42,664 DEBUG examining: 'deb ftp://ftp.fu-berlin.de/linux/ubuntu/ bionic main restricted' 2020-09-08 20:07:42,664 DEBUG verifySourcesListEntry: deb ftp://ftp.fu-berlin.de/linux/ubuntu/ focal main restricted 2020-09-08 20:07:42,664 DEBUG url_downloadable: ftp://ftp.fu-berlin.de/linux/ubuntu//dists/focal/Release 2020-09-08 20:07:42,664 DEBUG s='ftp' n='ftp.fu-berlin.de' p='/linux/ubuntu//dists/focal/Release' q='' f='' 2020-09-08 20:07:42,840 DEBUG error from ftplib: '550 SIZE not allowed in ASCII mode' 2020-09-08 20:07:42,841 DEBUG entry '# deb ftp://ftp.fu-berlin.de/linux/ubuntu/ bionic main restricted' was disabled (no Release file) 2020-09-08 20:07:42,842 DEBUG examining: 'deb ftp://ftp.fu-berlin.de/linux/ubuntu/ bionic-updates main restricted' 2020-09-08 20:07:42,842 DEBUG entry '# deb ftp://ftp.fu-berlin.de/linux/ubuntu/ bionic-updates main restricted' was disabled (no Release file) Please switch to using http and try the upgrade again. ** Changed in: ubuntu-release-upgrader (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1894885 Title: error while upgrade ubuntu 18 LTS to 20 LTS: comm: /var/log/dmesg: No such file or directory To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1894885/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
