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z420 reset loop after BIOS v3.91 update

Microsoft Windows 10 (64-bit)

Hi how are you. I have been reading the forum in search of a solution for my z420.


I recently updated my BIOS to v.3.91 under windows 10 with the HPQFlash utility. When the update had completed, windows gave a a blue screen with an error message saying the system needed to restart.


Once it restarted it went straight into a reset loop with the same symptoms described here:




I know from the maintensnce PDF the designator E15 is the ROM bootblock recovery header.

When I place the jumper on pins 2-3 I get the reset loop, the system reboots every second constanly. If I place the jumper on pins 1-2 it just switches on without video output to the monitor and after 1 minute the fans start to spin a full speed.


Same as described here:



I would appreciate any help you could give me.


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