There is new firmware available on the HP site for my printer, a HP Color LaserJet CP2025dn, but seems to be only available as a Windows executable.
How do I upgrade my printer's firmware using Ubuntu?
Sometimes a firmware upgrade can also be done from a virtual machine running Windows but I have no experience if this works in your case. If you do so, then there is a great risk for spoiling your hardware EPROM (e.g. if the virtual machine or the USB connection crashes at some point during the upgrade process).
I recommend the far easiest and safest way: plug in any PC/Laptop running Windows2000 or later, upgrade from there and be happy.
Well, here's how I managed to do it: I ran the Windows firmware update utility under Wine and it worked.
I don't recommend this solution as a lot of things could go very wrong by doing it, but it worked for me.
I wish HP would have a tool for Ubuntu users.
Normally hp firmware is loaded into the device at runtime, you don't need to really manage the firmware as hplip will come with the latest available.
It may be possible to extract the firmware from the exe and give it to hplip for your printer, but it would be hassle.
http://hplipopensource.com/hplip-web//tech_docs/man_pages/index.html
For the record, I've just updated my CP2025dn firmware using wine, from the command line. Nevertheless, it's not a recommended procedure, so be sure to use this information at your own risk.
wine CP2020_Series_FW_Update-20140702.exe
was all it took.
Cheers!