Install grub on jfs formatted /boot partition and reboot? you'll see: GRUB Loading stage1.5. GRUB loading, please wait... And the system become unresponsible Reproducible: Always Steps to Reproduce: 1. install grub on jfs partition 2. reboot
That's an interesting configuration ...
May be it's not grub bug. Turn on NC flag in cfdisk on this partition([Maximize]) and reformat it. Install grub. Grub works as expected.