Dell G5 15 5590 - no ram detected after setup_var_3 commands

BIOS/UEFI Modding BIOS Modding Guides and Problems
1

I did change some settings with grub so i could undervolt the cpu and all worked.

As i wanted to change settings for the ram, i must have done a typo or so.

Now i only get the led code for “no ram detected”.

I have installed new sticks but still cant boot or get any signal on the screen.

Are settings done with setup_var_3 commands not resettet if doing rtc,cmos,bios resets ?

Any chance i can revert my mistake ?

On which level are var command saved that no reset is fixing it ?

Is it possible to flash a bios directly on the chip or do i need a new board ?

2

You might have set up the timings too hard to get the ram even initialized after a cold boot. These settings are mostly stored in NVRAM which is a section in the normal firmware in the same SPI chip. These won’t get reset by CMOS jumper, maybe with bios settings reverted to setup defaults, but you possibly can’t get into bios settings now.

There are quite a lot of descriptions of people bricking their machines this way. You need a programmer, get a valid dump of your firmware, reverting NVRAM to stock and flash that again, it’s described several times here.

3

Hey, thanks for your response !

I didn’t know what I should have searched for as I lacking a lot of knowledge in this field. Searched now for days but concentrated on my notebook model.

I didn’t go over the stock mhz of those ram.

If I did a wrong command it would not have accepted and saved it right ?

I think I changed the frequency from auto to 2600. But 2666 rams also don’t get accepted.

I have done several rtc resets which should also set bios settings to default ( also nvram ).

Yes, unfortunately I don’t get any signal on the display without detecting the ram.

Is it possible to flash without soldering ?

4

When setting the variables manually there’s no security.

No.