ROG STRIX Z370-E POST fail: green LED lit

[Etheradur]

Hi all,

I just assembled a new PC with a ROG STRIX Z370-E and everything seemed to work fine at a first glance. I had the BIOS updated to 0605, and I had memtest-86 run several passes successfully to test my memory (one of the first things I usually do with new hardware). However, after making changes in the UEFI, the system doesn't boot any longer. In particular I changed the CSM (Compatibility Support Module) from enabled to disabled. After the reset, the system doesn't pass the POST any more. After a reset, first, the red LED (CPU) flashes quickly, then the orange LED (DRAM) for a second, then the white LED (VGA) for a second, then the green LED (BOOT) goes on and stays lit. I see nothing on my display (connected via DP to the Mobo).

I tried to solve the problem by turning off the computer, unplugging the power cord, removing the battery and short-circuiting the CLRTC jumper for a few minutes. It didn't help. I've read somewhere else that the CLRTC jumper needs to be short-circuited for about 24 h in some rare cases, what I'm currently doing. However, I have doubts that it will resolve the issue.

I've found in the manual that this Mobo has a CrashFree BIOS flashing feature, but the description isn't really precise. I have several questions about this:
- Should I rename the BIOS file on the USB drive to something particular? I know that older Asus Mobos required this. The manual of the Z370-E just says to copy the BIOS file to a FAT-formatted USB drive.
- In which port should I plug the USB drive?
- In which order should I power on the computer and plug in the drive?

I'll try to flash the BIOS if the CLRTC method doesn't help. Any other suggestions?

[Etheradur]

Hi all,

I revived my Mobo by short-circuiting the CLRTC jumper for > 24 hours while having the battery removed! I'm surprised that it helped, as I had tried to reset it several times this way for about 10 minutes without success.

[Nohus]

First of all, thank you Etheradur for your solution. I had the same problem: green BOOT (or BOOT_DEVICE) LED stayed lit on the motherboard, no output at all on the screen. My motherboard is ASUS ROG STRIX Z370-F GAMING (adding as much info as possible so people can find it when searching the internet). In my case I had a working computer, disassembled it for transport, assembled it again and encountered the problem for no apparent reason. I tried disconnecting parts, using the CLRTC jumper and removing the battery. None of it worked. Then I left the jumper on with the battery taken out for 8 hours and it just started working. It seems that 24 hours are not needed. In my case 8 hours was enough, it's probably a lot less, but when I tried for 5 minutes it did not help, so there really is some point in leaving it like that for a longer period.