I am on MacOS 10.14.6 and I have installed Windows 10 on the external SSD drive.
I was getting bless tool error and I have tried to do EFI bootable with Winclone 7.
I have disabled the SIP as well.
Please help.
Try mounting the EFI partition by running:
sudo diskutil mount disk0s1 and see if it gives an error.
Also, run:
diskutil list
and verify that EFI is on disk0s1.
tim