Print Error will not reset or clear on HP OfficeJet Pro 8600

[mark_taylor]

Referencing https://h30434.www3.hp.com/t5/Printing-Errors-or-Lights-Stuck-Print-Jobs/Event-Code-72234/m-p/673817...

None of the reset suggests reset the error.  Printer's web page indicates it's happy with all four genuine HP inject cartridges.  Performed all the suggested steps above, still have event 72234 showing in the log, and a printer error on the printer display, will not reset.  This began with an upgrade to the most current version of firmware, and I don't have an older version to downgrade to, factory reset suggestions also do not work.

Removed and reset all four cartridges four plus times, they don't leak.  Removed and reset printhead entirely, cleaned,  reinstalled, nothing on the carriage path.  Repeatedly removed and replaced printhead.

Printer control panel will not clear of error, so I cannot perform the clean printhead operation, need to clear that error first.

I have unplugged the printer for over 24 hours.  Unplugged the power with the printer on and waited 20 seconds to power up.  I've tried to push the back button repeatedly on power up, but the back arrow doesn't appear with the error message.  Can't recall how many other reset suggestions I've tried.

The original firmware is available on HP's site, but it requires a userid and password to access.  First version of the firmware is found at: ftp.hp.com/pub/networking/software/pfirmware/ojpro_8600_n911_a_1304A_10042013.ful.rfu - accessing with a web browser opens a web page with the code, but saving as an EXE does not work.  FTP OPEN sometimes works, but subsequent GET requires a userid and password.

Of course, even with the original microcode, it probably won't override newer firmware...

I've got a nice printer full of HP ink with an error that won't clear.

Just need a clear error routine that works, factory reset that works, or a firmware downgrade that works.

Thanks.