Color Laser Jet Pro 254dw 79 service error

[KB460]

For Color Laser Jet Pro 254dw with 79 service error and constant reboot cycle.  Running macOS 26 Tahoe. Printer is and has been connected wirelessly only; no cables.

Had this. printer for years without trouble. Suddenly got the above error message. Tried all the online recommendations including shutting down for several minutes, eliminating surge protector, and disabling wireless function. Nothing worked. Bought a factor refurbished unit since I had $300 in new HP toner cartridges. 

Installed new (refurbished printer) and immediately following updating firmware, same error message and symptoms. I've only been able to get as far as allowing "down grading the firmware" option and then it reboots. 
I'm highly suspicious HP put out a faulty firmware update and as mentioned, I have only HP brand toner. Any suggestions on how I might fix this or roll back the firmware given the rebooting problem?

Thank. you in advance for any suggestions!

[Kuroi_Kenshi]

Hi @KB460,

Welcome to the HP Support Community!

I understand how frustrating this situation must be. You experienced a 79 Service Error and continuous reboot cycle on your original HP Color LaserJet Pro M254dw, and the same issue appeared on a factory-refurbished replacement immediately after the firmware update.

To help determine the appropriate step, could you please confirm:

Does the refurbished printer display 79 Service Error immediately after powering on, or only after the firmware update?

Are you using genuine HP toner cartridges or third-party cartridges?

Do you recall the firmware version installed before the update?

Were you able to access the printer's menu or Embedded Web Server before the reboot cycle began?

Since you have already attempted the standard troubleshooting, I recommend the following:

Avoid repeatedly attempting an unsupported firmware downgrade. Do not interrupt the printer during a firmware operation or use unofficial firmware files.

If you can access the printer's control panel before it reboots, check whether you can restore the printer to its factory defaults using the supported menu options.

Let me know how it goes.

Best regards,

Kuroi_Kenshi