Comment 57 for bug 1644498

My system had the following packages upgraded:

Upgrade: linux-headers-generic:amd64 (4.4.0.130.136, 4.4.0.131.137), linux-libc-dev:amd64 (4.4.0-130.156, 4.4.0-131.157), linux-image-generic:amd64 (4.4.0.130.136, 4.4.0.131.137), linux-generic:amd64 (4.4.0.130.136, 4.4.0.131.137)

After that, there were errors again whenever I did `sudo apt update`. I opened `/var/cache/app-info/xmls/fwupd.xml` as `sudo`, went to line 256 and changed symbol `&` to `&`, saved the changes, and ran command `sudo appstreamcli refresh --force`. Thereafter, no errors appeared during `sudo apt update`. W/o running command `sudo appstreamcli refresh --force` the error persisted.

Hope this finding will be helpful to others in the same situation.