Hi Johnny,
Weird, I cannot even boot the installation media on my Legacy BIOS MSI laptop, it gives a disk error unless I change the bootmgr file with the one from Dev 23619 or any other older Canary builds before 25967.
The same problem with previous Canary builds starting with 25967 and on all the way to 26020.
I isolated the 1st one with this issue was 25967.
At this point I don't know what is different from your legacy Bios machine.
It fails just booting from the USB flash installation media from 25967 and up.

Looks to me that bootmgr in these last several Canary builds is pointing to the wrong disk and gets disk error on this MSI GT70-0NC laptop, but I'm afraid I will never figure out what exactly they changed to cause this problem. All older insider builds and Canary 25951 and below still work just fine. 😂😂😵💫🤐🤬🤷♂️