This has nothing to do with coreboot, the message is from the UEFI
payload (Tianocore/edk2). It's telling you that whatever boot device
it is trying to boot (and it tells you in the error msg) does not
contain a UEFI-bootable 64-bit OS. If you didn't install ChromeOS Flex
to your internal storage, then that is why (since ChromeOS proper is
not UEFI-bootable).

On Mon, Sep 5, 2022 at 9:10 AM CJ <christopher.galliart@gmail.com> wrote:
>
> First, I just want to thank all of you for what you do.  Using Coreboot is delightful.  I had a question about how the program verifies UEFI OS's.  I'm using it to update a chromebook to ChromeOS flex and receiving the error; doesn't contain a verifiable 64-bit UEFI OS.d From the documentation ChromeOS Flex is supposed to be a 64 bit UEFI so I"m wondering if it could be something I did while creating the boot media, a problem with updating chromebook, or how coreboot is verifying the OS?  After entering the menu I can boot to the USB and install just fine so no big deal just curious why it gave that error.  Thanks again for putting in the work!  We all appreciate it.
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