Intel's RAID is implemented in their driver. Switching the option from AHCI to RAID switches the disk controller's ID so it doesn't bind to the OS's standard driver (whichever OS that is), and binds to Intel's instead (assuming it's present). Intel provides its driver (and only for Windows), Lenovo locks the option so that hapless users mucking about in the UEFI settings don't make their machines unbootable.
Lenovo can deny "deliberately blocking Linux", but they can't deny "practically blocking Linux".
I was imprecise. The chipset supports a Linux-compatible option, were it not explicitly disabled in the firmware.
> Lenovo has issued a formal statement denying it.
They deny purposefully disabling Linux, and I don't have any evidence against that denial. They don't deny disabling AHCI, because they clearly did. In the disassembly of the code: https://lnv.i.lithium.com/t5/image/serverpage/image-id/76843...
Intel's RAID is implemented in their driver. Switching the option from AHCI to RAID switches the disk controller's ID so it doesn't bind to the OS's standard driver (whichever OS that is), and binds to Intel's instead (assuming it's present). Intel provides its driver (and only for Windows), Lenovo locks the option so that hapless users mucking about in the UEFI settings don't make their machines unbootable.
Lenovo can deny "deliberately blocking Linux", but they can't deny "practically blocking Linux".