On 8/27/20 5:01 PM, Robert McBroom via users wrote:
What does one do in the new environment to run different versions of linux on different drives of a system. One system has f31 on sda and centos7 on sdb. With legacy grub I could call the boot of one system from the other and vice versa. No more. Switching drives in the bios no longer works. I can kludge things by putting the boot files from the centos7 system in the f31 boot and putting the boot stanza in the as a custom entry in grub.d along with the stanza for Windows. All the entries in /boot/1oader point to the f31 system. grubenv is only appropriate for f31.
Boot a CentOS 6 live image and install GRUB legacy (assuming that your system is configured for legacy/BIOS boot). Totally deprecated, unsupported, politically incorrect, etc., etc., and far more functional than GRUB 2.