Grub 2:2.06.r322.gd9b4638c5-1 won't boot and goes straight to the BIOS after update

Ok. my first computer broke with this so I followed live usb > mount > chroot > make grub cfg > install grub
But when I boot I get the grub rescue prompt:

error: symbol grub_debug_malloc not found.
Entering rescue mode…
grub rescue>_

So, I tried with another EOS computer which I hadn’ t updated yet. Updated everything then installed grub as indicated in wiki guide.
But I had the exact problem! it boots into grub rescue with grub_debug_malloc error.

Any ideas!
thanks!