Comment 13 for bug 1647936

@gerald: right, there is no way to protect you from turning the device into a brick if this step goes wrong (unlike kernel or rootfs we can not roll back the bootloader)

note that the gadget snap from edge will not have a working dtb for the old kernel which will likely make you end up with an unbootable device. sadly on the pi the dtb gets loaded by the binary blob which is why we can not just use it from the kernel snap (which would fix this problem).