Windows 10/gentoo linux dual boot killed

[Drake Donahue]

I installed the M$ April update yesterday on four gentoo/windows (3 win10, 1 win 11) double booters. Also updated malicious software removal tool. Later today all four PC's cannot boot gentoo minimal install disks but can boot a Windows 10 install disk. The win 11 also boots win 11 install disk. The installed gentoos are now invisible, not bootable or runnable. I have been running dual boot for 17 years, one of these machines was my first uefi dual boot about 10 years ago. This is a first. My assorted uefi/bios report secure boot disabled, I suspect M$ update(s) attacked directly in the uefi/bios. My available boot devices show only windows boot manager in some cases in others some legacy devices appear (unbootable).

SO: BE WARNED!

Ideas for a workaround welcomed ...

 

[Bighorn]

No particular solution but what I've seen over the years on forums' discussions with dual-booting is that changing/upgrading one OS frequently screwed up the other OS requiring reinstall, generally the same was as originally done. I got the notion from those postings that using a VM was easier to do, setup. I run Win11, Win10, Win7 and Linux Mint through a KVM switch, 4 Desktops connected to 1 Keyboard, 1 Video/monitor and 1 Mouse. Only the Win11 is the newest, about a year now, other machines I salvaged and work fine.