I've noticed for a while running memtest from grub2 menu just gives a blue screen and locks machine.

Had a similar issue running it from grub4dos, but found running syslinux memdisk and then running program worked, but exact same thing didn't work with grub2??
So, just tried using the iso versus the memtest.img extracted from it, and that comes up.

Manually modifed the grub.cfg by coping section that Fedora creates and making changes??
Have seen messages saying it was broken, but never found any fixes. So, not sure some can tell why? or if this would be useful to others to try??


### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry 'Fedora Memtest memtest86+-5.31' {
              insmod part_msdos
              insmod ext2
              set root='hd0,msdos5'
              if [ x$feature_platform_search_hint = xy ]; then
                search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos5 --hint-efi=hd0,msdos5 --hint-baremetal=ahci0,msdos5 --hint='hd0,msdos5'  fa908208-22bd-4031-b620-841498e0708c
              else
                search --no-floppy --fs-uuid --set=root fa908208-22bd-4031-b620-841498e0708c
              fi
              insmod bsd
              echo      'Loading Fedora Memtest memtest86+-5.31 ...'
              knetbsd /elf-memtest86+-5.31
}
menuentry 'Memtest' {
              insmod part_msdos
              insmod ext2
              set root='hd0,msdos5'
              if [ x$feature_platform_search_hint = xy ]; then
                search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos5 --hint-efi=hd0,msdos5 --hint-baremetal=ahci0,msdos5 --hint='hd0,msdos5'  fa908208-22bd-4031-b620-841498e0708c
              else
                search --no-floppy --fs-uuid --set=root fa908208-22bd-4031-b620-841498e0708c
              fi
           echo 'Loading memdisk'
           linux16 /memdisk iso
           echo 'Loading iso'
           initrd16 /memtest86+-5.31b.iso
}


### END /etc/grub.d/20_memtest86+ ###