Roberman,
0. Verify that the current BIOS is not blocked from reversion.
1. Set a maximum 1GB** MBR, FAT32 partition on a USB drive. It is helpful if the flash drive has an activity indicator.
___ **1GB is based on zX20 BIOS file size. Confirm the capacity of BIOS for zX40.
2. Copy the selected *.bin BIOS file to the root directory of the prepared partition.
3. With the system, off insert the USB drive into a front panel USB 2.0 port.
4. Start the system. The USB LED should (if similar to zX20) show activity and indicate flashing BIOS with a display progress slider.
5. The system should finalize with a BIOS successfully updated message.
6. Shut off the system,
7. Remove the USB drive
8. Reboot to BIOS
9. Note that the BIOS version was successfully reverted.
__ Be aware that there have been historically, more than one HP BIOS version that can not be reverted, except by invoking the crisis recovery subsystem. I discovered this when trying to revert z620 BIOS from v3.92 to v3.91. In this example, a reversion was not allowed as the 3.92 version contained Spectre / Meltdown protection.
May I ask the reason for the reversion?
Let us know how it goes.
BambiBoomZ
HP z620_2 (2017) (R7) > Xeon E5-1680 v2 (8-core@ 4.3GHz) / z420 Liquid Cooling / 64GB DDR3-1866 ECC Reg / Quadro P2000 5GB _ GTX 1070 Ti 8GB / HP Z Turbo Drive M.2 256GB AHCI + Samsung 970 EVO M.2 NVMe 500GB + HGST 7K6000 4TB / Focusrite Scarlett 2i4 sound interface + 2X Mackie MR824 / 825W PSU /> HP OEM Windows 7 Prof.’l 64-bit > 2X Dell Ultrasharp U2715H (2560 X 1440)
[ Passmark Rating = 6280 / CPU rating = 17178 / 2D = 819 / 3D= 12629 / Mem = 3002 / Disk = 13751 / Single Thread Mark = 2368 [10.23.18]
