I am having the same issues on my 3538, but I do not have a choice on the boot sequence. I can get to the Add Boot Option, but when I add the 123 I do not have a drop down for the file system or therefore the directories. I can eventually get to the Input file path name, and tried entering what you had - \EFI\BOOT etc - but I'm just not sure what to do with it afterward since my system looks different than yours.
Obviously I don't really know what I am doing, but I did just replace the hard drive 2 weeks ago and was working fine after I installed all the updates.
Can you walk me thru it since your method seem to work for everybody else?