Why does grub-mkrescue create a broken/empty iso, virtualbox says "FATAL: Could not read from the boot medium! System halted."?

Question

linux

I am following this course exactly .
Version difference + Debian author, I have Win7x64 -> VMWare -> Kali-light64.
At the moment in the video 34:42, the author's iknow.iso weighs 1.9mb, mine has 383kb.
I downloaded the author's sources - his iso works, but the build with his sources gives me the same 383kb and a non-working/empty iso.
Googled 2 identical questions with no answer...
stackoverflow.com/questions/39517591/grub-mkrescue...
stackoverflow.com/questions/29465736/generating-an...
tried to build an example from the second question (baremetal helloworld), creates . img, the result is the same - 387kb, does not load.
Assembly according to the author's sources:

[email protected]:~/Desktop/IKnowOS# grub-mkrescue -v -o iknow.iso iknow/
grub-mkrescue: info: temporary iso9660 dir is `/tmp/grub.hjhBBe'.
grub-mkrescue: info: executing xorriso -as mkisofs -graft-points --modification-date=2016091715411900 --protective-msdos-label -o iknow.iso -r /tmp/grub.hjhBBe --sort-weight 0 / --sort-weight 1 /boot iknow/.
xorriso 1.4.4 : RockRidge filesystem manipulator, libburnia project.

Drive current: -outdev 'stdio:iknow.iso'
Media current: stdio file, overwriteable
Media status : is blank
Media summary: 0 sessions, 0 data blocks, 0 data, 3390m free
Added to ISO image: directory '/'='/tmp/grub.hjhBBe'
xorriso : UPDATE : 3 files added in 1 seconds
Added to ISO image: directory '/'='/root/Desktop/IKnowOS/iknow'
xorriso : UPDATE : 7 files added in 1 seconds
ISO image produced: 187 sectors
Written to medium : 187 sectors at LBA 0
Writing to 'stdio:iknow.iso' completed successfully.

grub versions:
grub (GNU GRUB 0.97)
xorriso versions:

xorriso 1.4.4 : RockRidge filesystem manipulator, libburnia project.

xorriso 1.4.4
ISO 9660 Rock Ridge filesystem manipulator and CD/DVD/BD burn program
Copyright (C) 2015, Thomas Schmitt <[email protected]>, libburnia project.
xorriso version   :  1.4.4
Version timestamp :  2016.07.01.140001
Build timestamp   :  -none-given-
libisofs   in use :  1.4.4  (min. 1.4.4)
libjte     in use :  1.0.0  (min. 1.0.0)
libburn    in use :  1.4.4  (min. 1.4.4)
libburn OS adapter:  internal GNU/Linux SG_IO adapter sg-linux
libisoburn in use :  1.4.4  (min. 1.4.4)
Provided under GNU GPL version 3 or later, due to libreadline license.
There is NO WARRANTY, to the extent permitted by law.

Answer 1

The problem was solved by replacing grub with version 2.02~beta2-36.
True, the generated iso for some reason is more than 3 times larger than that of the author, but the main thing is that it is loaded.