If you can see the option I enabled (with IDE/ACHI/RAID) then it's already unsuppressed or it wouldn't be visible.
This may be locked by your NVRAM holding in AHCI as set default option. Please send me FPT BIOS region dump, while using the unlock BIOS I sent you flashed in, then i will change it all to IDE in all NVRAM areas, then you flash again by FPT

Here is the dump of the bios (I unlocked chipset setting):

@XPWELL64 - Is that a "DUMP" from your system, then you modified? If yes, please remove from the other thread or tell me to delete that post, no one else can use "Dump" from your system modified, only stock BIOS can be modified in that manner for use with other peoples systems.

Yes it is a dump.

Please flash BIOS I sent you at post #12, then make FPT Dump of BIOS region and send to me. Then I will edit again and make all NVRAM set to IDE only as well.

I flashed it but it still shows ahci controller. Here is the DUMP of my BIOS:

@Lost_N_BIOS
Please answer me did you finish my bios modding? If yes, send me a bios link. I'm waiting for one day.
.

@Lost_N_BIOS
I'm waiting for it.

@Lost_N_BIOS
Please answer me did you complete my bios modding?

@XPWELL64 - Very sorry for the delays here!
I will edit the BIOS for you tonight

@Lost_N_BIOS
Did you complete my bios modding?

@XPWELL64 - Reading back, I think maybe there is some confusion here, maybe on my part too? After you flash BIOS in post #12, AHCI would still be an option, but you can then choose IDE, AHCI, or RAID - choose whatever you want.
Why do you want IDE anyway, it's much slower than AHCI mode. I can still do the edit I mentioned, to force IDE as default on everything, but wanted to wait and get clarification by you, what happens when you set IDE with BIOS in post #12 and reboot back to BIOS?
Is it reset back to AHCI then on reboot after you set IDE? If yes, we can force, but then it may not boot to any disk at all if IDE functionality has been removed from this BIOS in some way.
I wanted to make sure what's going on here, if you "See AHCI" as an option with BIOS #12 so you thought it wasn't changed still, or you already tested setting IDE and it still goes back to AHCI. Because AHCI option will always be a select-able choice in the BIOS, you just have to pick IDE instead.

Yes I want ide.

Yes, I understood that. Please answer my questions above (All of them)

I want retro OSes. I set up to IDE. BIOS shows as ide but when I install windows its disk controller recognises as ahci. When I reset, it recognises as ahci. The result is BIOS shows as IDE but windows shows as ahci.