Just installed F29 on a HP 15-g023cl and was checking things out post install and ran into this failed service I wasn't familiar with.

# systemctl status dbxtool
● dbxtool.service - Secure Boot DBX (blacklist) updater
   Loaded: loaded (/usr/lib/systemd/system/dbxtool.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Thu 2018-11-22 11:21:39 CST; 22min ago
  Process: 784 ExecStart=/usr/bin/dbxtool -a /usr/share/dbxtool/ -q (code=exited, status=1/FAILURE)
 Main PID: 784 (code=exited, status=1/FAILURE)

Nov 22 11:21:38 localhost.localdomain systemd[1]: Started Secure Boot DBX (blacklist) updater.
Nov 22 11:21:39 localhost.localdomain dbxtool[784]: Applying 1 updates
Nov 22 11:21:39 localhost.localdomain dbxtool[784]: Applying "DBXUpdate-2016-08-09-13-16-00.bin" 2010-3-6 19:17:21
Nov 22 11:21:39 localhost.localdomain dbxtool[784]: Could not apply database update "DBXUpdate-2016-08-09-13-16-00.bin": Invalid argument
Nov 22 11:21:39 localhost.localdomain dbxtool[784]: Cannot Continue.: Invalid argument
Nov 22 11:21:39 localhost.localdomain systemd[1]: dbxtool.service: Main process exited, code=exited, status=1/FAILURE
Nov 22 11:21:39 localhost.localdomain systemd[1]: dbxtool.service: Failed with result 'exit-code'.

I quickly found a few bugs, the oldest one is over a year old and was initally reported on F27! There seem to be suggested fixes but no maintainer action in some time.

https://bugzilla.redhat.com/show_bug.cgi?id=1508808
https://bugzilla.redhat.com/show_bug.cgi?id=1593258

Thanks,
Richard