a problem updating Z620 BIOS

[SDH]

"System requires a BIOS version of 01.07 or greater to update to the new 02.00 or 03.00 code base"

The above statement from HP seems to imply that you might be able to step straight up from your 1.08 to the latest 3.87 version directly, but it won't hurt to step first up to a 2.x version, and then straight up to 3.87 from there.

You don't need to do every BIOS update sequentially because the later versions include the earlier improvments, and may even improve some of the earlier improvements.  The presence of a threshold BIOS version to be reached before later BIOS updates can be done is unusual for HP workstations, but if one does not know this situation then you're stuck.

Big thanks go out to joselso for finding the early (and necessary) BIOS source, and the critical HP statement above. 

I hope one of our HP friends who check in on the forum can get the need for this information and early BIOS link back into the official HP drivers sources.

Attached below is a PDF of the HP communication joselo found, and you can extract the version 1.23 .bin file for the Z620 BIOS upgrade from the SP64701 .exe link in the PDF.  You could use that tiny .bin file for the upgrading of Z620 BIOS from within BIOS technique (from pre-1.07 to 1.23) if you download and run SP64701, and dig out the .bin file from that.  You can also run the SP64701 BIOS updater from within your OS, the common way. 

You also can run the SP and extract the .bin file from a non-Z620 computer, and save it on a thumb drive or in your archives for later use.  This makes updating BIOS from within BIOS in a "locked down" Z620 workstation pretty easy, using that .bin file on a non-bootable USB drive that you have inserted in the Z620 from cold boot.