@hancor - thanks for the unintended tip here! I checked your BIOS, and do not see CBS/PBS in AMITSE either, nor in the BIOS generally as a menu/settings thing, but I see bifurcation options like you mention @ Advanced >> Onboard Devices Config. I assume this is what you were referring to, correct?
If yes, these are also in aGeoM's BIOS at same location, need to see if they are hidden from view there or not, if they are then I can unhide easily
If these are not what you mean, please show me image of your BIOS so I can see where you see these and how they look etc - Thanks!

@KedarWolf - MSI BIOS is such a pain sometimes, nice to see that he could add for you like that, in that manner, and at that exact location (need to learn how!)

@aGeoM - For now, below is my related findings as I looked through your BIOS and AMITSE, but due to above I think I will pause until you show me image of your BIOS @ Advanced >> Onboard Devices Config page (if you cannot see this submenu let me know)
In block list / block list area (AMITSE #1 BODY >> 0x181BB0h)

4A 10 59 7B 0D C0 58 41 87 FF F0 4D 63 96 A9 15 10 27 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - Main
4A 10 59 7B 0D C0 58 41 87 FF F0 4D 63 96 A9 15 17 27 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - Chipset
4A 10 59 7B 0D C0 58 41 87 FF F0 4D 63 96 A9 15 1C 27 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - Security
4A 10 59 7B 0D C0 58 41 87 FF F0 4D 63 96 A9 15 1B 27 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - Exit
55 C8 1B 94 7E BF CB 4F 88 2F 7A EA D1 5C 9D 47 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ? ^^ All above, known/expected to be here
2E CF 39 5E 12 67 AB 45 84 C4 35 D3 C6 A3 68 6D = 668706B2-BCFC-4AD4-A185-75E79F3FE169 / NVMe controller and Drive information

71 99 03 93 45 85 04 4B B4 5E 32 EB 83 26 04 0E = C74F06D2-ED92-489B-879C-C0E428A22167 / RAIDXpert2 Configuration Utility
0C C2 2F F2 F4 8C EB 45 8E 06 AD 4E 50 B9 5D D3 = ?

Both of the above could possibly be CBS/PBS, unsure, or links to them maybe? Or, CBS/PBS simply removed from AMITSE in this BIOS, so instead of 00/FF them out like previous edit method, you'd have to add them in at an allowed and or visible list instead.
I found three CBS modules in this BIOS too. I see no CBS (E3 35 45 B0 04 30 46 49 9E B7 14 94 28 98 30 53) in AMITSE, so it's not about adding CBS/PBS here then, unless it's referenced in some other way in AMITSE than we previously know.

Anyway, at the above menu location which I ask you to see image of, you have bifurcation options there, so if that is your main goal for PBS visible access, then we can make this visible for you instead
Never mind, well still show me this, but I just realized there is not bifurcation setting there only options to set lane width or RAID mode per slot I need to see what Hancor see's in his BIOS, maybe then I can do something here.
I don't work a lot with AMD BIOS, but I do work often with AMI BIOS, so I can manipulate AMI BIOS fairly well, but CBS/PBS is often tricky for me due to how it's implemented into the menu (ie I mainly knew the method you linked for this)

@ket may be able to better help you find a way to make PBS visible in your Asus ROG-STRIX-X570-E-GAMING BIOS ?

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