Recently had to log into a few of the RHEL6 systems that I manage via grub, in order to reset the Root password.

I wasn't able to get in via the grub passwd that I set, which was a complex, 15 character, mix of alpha-numeric characters.

I later used a live disk to remove the Grub password and set a simple password for grub and it worked.

I consulted the man and info pages for grub-md5-crypt, however I can't find anything stating if there is a character limitation. I also looked at the grub home page and can't find anything there either.

Do we know if there is a character limitation when setting a passwd for Grub?

thanks

Yeah, seems that 31 characters is the limit: https://lists.gnu.org/archive/html/b.../msg00024.html