I Rambooted manually using new grubx64.efi the Mini-10x64.vhd of 2.3 GB and this time I looked carefully the screen before running boot command, in my case there is no Failed to allocate on memory (as on wimb photo).
On allocating memory it reported 100% and latter on whrite grub4dos drive map slot it reported 99% but no failure reported.
NOTE: This PC has 8 GB of Ram.
I made another discovery since yesterday but talking about other things forgot to comment it, I'm stil using on this VHD the unsigned version 1.2 of SVBus driver and after first boot I found there is no need on future boots to keep enabled Test Mode (Testsigning) or No integrity checks or LoadOptionsString DISABLE_INTEGRITY_CHECKS on EFI BCD. See attached picture.
alacran
So you have also the write grub4dos message !!!!
I am booting in UEFI Secure mode and you in UEFI mode.
May be that is the reason that in your case the failed to allocate memory does not appear
And in your case UEFI Grub4dos is working OK, whereas in my case I get boot_image_handle not found ....