@secsvy
Welcome to HP Support Forums.
I came across your post and would like to assist you.
I understand that you're looking for a wpa2 password for the firmware update for your HP OfficeJet Pro 8710 All-in-One Printer. I'll be glad to help you.
To begin with, you can try to update the printer using the printer's front panel menu as shown below:

NOTE: The printer needs to be restarted once the firmware is successfully updated.
If it is the Wi-Fi direct password then it should be 12345678.
You could also check for the Wi-Fi Direct password on the printer's screen by following the below steps:

Alternately, you may check this HP link to find the Wireless WEP, WPA, WPA2 passwords.
I sincerely hope this information helps. Please feel free to keep me posted for further assistance.
Cheers!
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