Comment 61 for bug 1396379

> It doesn't corrupt boots. It's inconvenient.

Yes, it does corrupt boot setups. I'm not sure how you can say it doesn't.

I mean I guess TECHNICALLY it "only" overwrites working boot setups, with non-working boot setups; it's not actually corrupting existing files with garbage data.

My encounter with this bug, several years ago now, was when I was trying to set up a USB stick my daughter could plug into her crappy notebook laptop to boot to Xubuntu, but leaving Windows installed on the laptop itself. I wanted it as dead-easy as possible. Boot with USB inserted: boots to Xubuntu (stored on the USB). Boot without USB: boots to Windows. Like a live USB, but a full install which we could keep up-to-date and with writable storage for files and a user profile and stuff.

I painstakingly partitioned the USB as needed, and selected the partition on the USB to install grub to.

Result: Windows bootloader on the laptop's eMMC storage replaced with grub configuration that can only boot with the USB inserted. Windows was no longer able to boot normally at all. I did eventually fix it and get it to the state I wanted. But initially, the Ubuntu installer absolutely ignored my explicit instructions and therefore completely broke a working setup. I'm pretty sure (my memory is fuzzy from several years ago) I needed to resort to restoring a full-disk backup image to fix the Windows install. Either that, or I used some sort of recovery tool to fix a nonfunctional EFI partition.

That's way beyond just being "inconvenient".