EFI booting from external USB pen drive

Hi,

while I can boot memstick images just fine (which are created using 
makefs/mkimg), doing the same thing using gpart/newfs_msdos -F 12/.. I 
am not able to get anything that boots.

On a Thinkpad (secure boot is off) from the “boot device chooser from 
‘BIOS’” I get a quick blank screen and am back at the chooser.  
I’ve tried the gpart “thinkpad hack” as well as trying an MBR (why 
that should work I don’t know but the memstick one does) and GPT 
options of various kinds.


Anyone successfully done this lately?


/bz