Question A1 and A2 Ram slot N/A while B1 and B2 works (4 memory sticks)

[Nehui]

Posting this here because I don't know wether is a mobo problem or RAM
B550M DS3H (Gigabyte)
32gb Aorus ddr4 3733mhz (4 sticks 8gb each)
Ryzen 5 5600x
ASUS RTX 3060
So I was playing beatsaber on my oculus quest 2 when I ran out of battery and it went off, took my headset out and when I was about to close beat saber via alt f4 my pc freezed (I think it was SteamVR making it crash). After that I got no signal from my displayport, tried with my second monitor via HDMI but it didn't work(My graphics card fan was spinning,also cpu and RAM leds were on). Took my GPU off to realise I had a Ryzen 5 5600x which can't give video without a graphics card so I took all my ram off minus the A1 slot which is the one closer to the cpu and I had to dismount my 212 evo cooler to take out.
PC booted to bios and tell me something about that config wasn't good for starting or something (can't remember the whole message), so I picked the option to restart the optimized settings which disabled my tpm ,but before I realized why windows couldn't retrieve my pin, I just reinstalled windows...
Then reinstalled my 4 sticks and saw that only B1 and B2 Ram slots were working, A1 and A2 shows like N/A. Tried only A2 B2, it works. Tried A1 B1, only B1 appears to be working. What's causing my a big headscratch is that I booted A1 alone just before. Any ideas?

 

[autoblogart]

Posting this here because I don't know wether is a mobo problem or RAM
B550M DS3H (Gigabyte)
32gb Aorus ddr4 3733mhz (4 sticks 8gb each)
Ryzen 5 5600x
ASUS RTX 3060
So I was playing beatsaber on my oculus quest 2 when I ran out of battery and it went off, took my headset out and when I was about to close beat saber via alt f4 my pc freezed (I think it was SteamVR making it crash). After that I got no signal from my displayport, tried with my second monitor via HDMI but it didn't work(My graphics card fan was spinning,also cpu and RAM leds were on). Took my GPU off to realise I had a Ryzen 5 5600x which can't give video without a graphics card so I took all my ram off minus the A1 slot which is the one closer to the cpu and I had to dismount my 212 evo cooler to take out.
PC booted to bios and tell me something about that config wasn't good for starting or something (can't remember the whole message), so I picked the option to restart the optimized settings which disabled my tpm ,but before I realized why windows couldn't retrieve my pin, I just reinstalled windows...
Then reinstalled my 4 sticks and saw that only B1 and B2 Ram slots were working, A1 and A2 shows like N/A. Tried only A2 B2, it works. Tried A1 B1, only B1 appears to be working. What's causing my a big headscratch is that I booted A1 alone just before. Any ideas?

1) First of all go to bios reset to default everything and shutdown pc and now install all 4 ram sticks and try again

Try disabling xmp and look again if it works at standard 2666mhz

2) now if it didnt work update your bios to the latest version and try again.

Start with step 1 first then 2

 

[Nehui]

1) First of all go to bios reset to default everything and shutdown pc and now install all 4 ram sticks and try again

Try disabling xmp and look again if it works at standard 2666mhz

2) now if it didnt work update your bios to the latest version and try again.

Start with step 1 first then 2

Just updated my bios, before my ram showed 2333mhz or so even when xmp was active, now it goes up to 3733 but putting the 4 sticks gives me a black screen instead of the 2 disabled A1 A2. So I'm back at the start.
Edit: Pressing the power button to turn off at this state Cause the power button to blink all the time which makes me power off from the psu
Edit2: I was ready to give up after clearing cmos and getting no signal with the 4 sticks, then tried A2 B1 B2, it worked, added A1 and worked, I'm so mad that I can't seem to realise what was the problem or what caused it, I hope someone could explain.

 

[curs3d]

Just updated my bios, before my ram showed 2333mhz or so even when xmp was active, now it goes up to 3733 but putting the 4 sticks gives me a black screen instead of the 2 disabled A1 A2. So I'm back at the start.
Edit: Pressing the power button to turn off at this state Cause the power button to blink all the time which makes me power off from the psu
Edit2: I was ready to give up after clearing cmos and getting no signal with the 4 sticks, then tried A2 B1 B2, it worked, added A1 and worked, I'm so mad that I can't seem to realise what was the problem or what caused it, I hope someone could explain.

Just created an account here because I was experiencing the same problem with a ryzen 3700x system that was previously stable with 4 sticks suddenly wouldn't post even after multiple cmos resets. I confirmed it wasn't the sticks or the slots by moving them around and stress testing but the second I filled all slots it wouldn't even post.

Your trick of filling all slots except the first slot booted up fine. Shutting down to add the fourth stick and it still boots without a problem and currently stress testing without any errors. What the hell? Maybe a new memory training AGESA bug? I'm using the latest 1.2.0.8

Thanks for sharing your experience, I had fully accepted the loss of using all dimms before finding this post.