Re: 'error: invalid signature' when booting Windows 10

[Pascal Hambourg]

Le 14/12/2018 à 06:13, David Collier a écrit :
> when I try booting from the usb stick it indeed shows two boot options,
> 'Patriot Memory PMAP' and 'UEFI: Patriot  Memory PMAP' but when I try
> picking the UEFI option it fails with message
>
> error: file '/boot' not found

Is this a GRUB error ? Does it fallback to a grub rescue prompt ? If 
yes, what do the 'set' and 'ls' commands display ?

> however, if I boot from this stick in non UEFI mode I see that it has two
> partitions, and both of them have /boot directory.
>
> Any idea what could be wrong? Some search suggests that it could be due to
> the fact that I copied the .iso image to the stick using dd, is this the
> case?

What ISO image is it ?
dd to /dev/sdX is the proper way to write the image if it is a 
ISO-hybrid image.

Instead of using an ISO image on the stick, you could also create a DOS 
or GPT partition table, an EFI partition (FAT) and a Linux partition 
(ext2 or ext4), mount the EFI partition on /boot/efi and the Linux 
partition on /boot/grub and run

grub-install --removable
update-grub

Then reboot and select the USB stick for boot in UEFI mode.