I've not done that, but first I'd recommend doing a backup/clone to the new drive with the old setup.

You might want to check out ...

"Move your Linux from legacy BIOS to UEFI in place with minimal downtime" by Vincent Cojot

https://www.redhat.com/sysadmin/bios-uefi

also...

"A BIOS to UEFI Tranformation" by Rod Smith

https://rodsbooks.com/bios2uefi/

regards,

Daniel Villarreal

https://www.youcanlinux.org/

On Wed, 24 Nov 2021 at 16:32, James Knott via talk <talk@gtalug.org> wrote:

... 1 TB SSD drive to replace 750 GB drive in ThinkPad... considering [changing] to UEFI.
I'll be mounting the old drive in an external case so that I can copy... partitions, one of them NTFS...