Something is wrong here. These '?' are the result of a printf %u format string... that shouldn't happen.
Not having right output makes it difficult to further debug and confirm whether this is a problem with shim or the uefi network driver or the grub binary or the tftp server.
The error message shown by shim in the screenshot is:
Malformed binary after Attribute Certificate Table >VirtualAddress : 0x002E6088
datasize: ? SumOfBytesHashed: ? SecDir->Size: ?
hashsize: ? SecDir-
Something is wrong here. These '?' are the result of a printf %u format string... that shouldn't happen.
Not having right output makes it difficult to further debug and confirm whether this is a problem with shim or the uefi network driver or the grub binary or the tftp server.
Opening a shim task.