This often happens to me with RESTART. Shut Down the computer then switch on & then the BIOS accesses with no problem.
BIOS: Cannot Access It After Restart (urgent)!
I am facing similar problem with my HP PoBook 430 G3. After installing Antegros I can enter BIOS only after shutdown and startup. Antegros will not allow me to enter recovery menu or boot menu because when I hit F11 for recovery menu or Esc for boot menu it will start to load but soon the Antegros grub flashes over. It seems like Antegros boot is too aggressive compared to other distros.
That’s a bit weird behaviour I did not have this problem with Fedora, Ubuntu or Zorin.