Desktop Boot and Lockup

Hi,

we currently have 5 HP Z2 Mini G9 desktops, which were purchased new by our customer (who has another 35 of them). When installing the first windows update, during the reboot process, the machine gives two long beeps (during the beeps the power led lights up red) and then switches itself off. After that it can't be rebooted (or so it seems), it will just beep once, and no signal is going to the monitor. The power LED will stay on, but the fan will turn itself off.

After trying a lot of things, I found out, that by hitting ESC at the right moment, it will actually boot (I tried to get into the BIOS, but that didn't happen, it just boots normally). This procedure is reproducible. Boot it normally, no image, nothing happens, hit ESC at the right moment, Windows boots as if nothing was wrong.

Then, when I was in Windows, I downloaded the latest BIOS upgrade (03.02.03 Rev.A, sp153011.exe). This claims that my bios is up to date, but something else is not. After upgrading that, everything went back to normal, and the computer starts normally again.

I then tried to first install sp153011 on the second PC. But it's not possible. When you execute sp153011.exe on a non-bricked Windows, nothing happens (i.e. no window opens that lets you install the update). I was then able to reproduce the entire procedure on the second PC. I.e. first brick it via Windows Update, then recover by hitting ESC, and repair with sp153011.exe.

However, I don't want to brick 40 PCs, hoping that I'll be able to recover by hitting ESC at just the right time. Is there some way to prevent all of this ordeal? Especially, is there a way to install sp153011.exe without first bricking the PC?

(Part of me writing this all down is in the hope of other people with the same problem at least finding out how to unbrick it.)