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ho z420 wont boot

HP Recommended
hp z420
Microsoft Windows 10 (64-bit)

workstation stuck at boot:

power switch on

power led flash green

power led goes blue

after 1minute fans goes 100% 

thats all

but beeps seems to work

clear cmos: no go better

remove ram only 4beep

remove graphic only 5beep

change graphic no go better

i want to know how to force a panictecovery cmos

with help of nondocumented panicrecovery switch between pci33/66 and pci-e16 slot

original is 2-3

when move to 1-2

power led flash red 8times


my question: is reflashing bios the right way?

thanks to all



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Message 2 of 3
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HP Recommended

Before you attempt the BIOS recovery procedure, I would recommend you check the maintenance and service guide. i.e. the fault you have may not necessarily be a BIOS fault.


Here's a link to the HP Z420 service and maintenance guide;  There is a section (page 149) that explains the various beep / error codes on these machines.


If you do need to perform a BIOS crisis recovery, then look for a post created by SDH that gives a very detailed procedure that must be followed. 

HP Z620 - Liquid Cooled E5-1680v2 @4.7GHz / 64GB Hynix PC3-14900R 1866MHz / GTX1080Ti FE 11GB / Quadro P2000 5GB / Samsung 256GB PCIe M.2 256GB AHCI / Passmark 9.0 Rating = 7147 / CPU 17461 / 2D 1019 / 3D 14464 / Mem 3153 / Disk 15451 / Single Threaded 2551
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Message 3 of 3
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There is a significant sized post in the forum here about the crisis recovery jumper and BIOS corruption.  May I ask... did your problem start after a BIOS update?  We have been seeing this more over the past few years, likely related to updating BIOS from within the operating system using the application for BIOS updating that was written for XP and W7 in the W10 environment. 


I have been harping on only doing BIOS updating from within BIOS, and have written in here about how to do that.  There also is a way to do that with a less primative operating system than BIOS..... by doing the upgrade from within DOS.


HERE  is that post:  

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