Removing a Hybrid MBR from a GUID-Partitioned Disk

I wasn’t planning to do all my Blaugust posts on tech stuff, but it seems to be working out that way this week. 🤷 Today I learned about hybrid MBR/GUID partition tables, where the GPT (not that kind) on a disk is duplicated in an MBR table for compatibility purposes. Those reasons are probably outdated, unless you’re running a really old operating system, because GUID partitions have been around a very long time now. According to Wikipedia’s chart you have to go back to Windows 7 to find an OS that can access GPT disks but not boot from them, and Windows Server 2003 (fixed in SP1) to find one that doesn’t recognize them at all. Fun fact 1: This means a disk can have an MBR pointing to a partition that MBR doesn’t support, like a multi-terabyte filesystem! Fun fact 2: If Windows sees an MBR, it doesn’t bother with the GUID table, and it insists that partition is invalid! (Yes, even if you specifically formatted it with exFAT so Windows could read it.) macOS at least used to…