Hello, my system (HP Z220 Workstation) was affected as well. Steve asked for more information on the users mailing list, which I try to provide here (it's my first use of the debian bug tracker).
1. Number of disks: 2 2. Filesystem setup grub is installed in MBR of /dev/sda # fdisk -l Disk /dev/sda: 238,5 GiB, 256060514304 bytes, 500118192 sectors Disk model: MTFDDAK256MAM-1K Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xb0e478ed Device Boot Start End Sectors Size Id Type /dev/sda1 * 2048 206847 204800 100M 7 HPFS/NTFS/exFAT /dev/sda2 206848 231323647 231116800 110,2G 7 HPFS/NTFS/exFAT /dev/sda3 231323648 365541375 134217728 64G 83 Linux /dev/sda4 365541376 500117503 134576128 64,2G 5 Extended /dev/sda5 365543424 382320639 16777216 8G 82 Linux swap / Solaris Disk /dev/sdb: 1,8 TiB, 2000398934016 bytes, 3907029168 sectors Disk model: WDC WD20EARX-00M Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: dos Disk identifier: 0x063dc1fc Device Boot Start End Sectors Size Id Type /dev/sdb1 2048 327682047 327680000 156,3G 7 HPFS/NTFS/exFAT /dev/sdb2 327682048 361236479 33554432 16G 82 Linux swap / Solaris 3. History of the system As far as I remember (don't know how to check) I installed Jessie / Debian 8 and upgraded to stretch, later to buster 4. Additional information # uname -a Linux xxxx-Debian 4.19.0-9-amd64 #1 SMP Debian 4.19.118-2+deb10u1 (2020-06-07) x86_64 GNU/Linux I was able to fix the boot problem by using a rescue system from the installer cd, mounting /dev/sda3 and then re-installed grub on /dev/sda (via the rescue system interface menu). This is a Linux / Windows dual boot setup. /dev/sda is a SSD, /dev/sdb is a HDD I don't know if this is relevant, but to be honest this computer has a rather "adventurous" history. I copied the linux system from another hard disk (maybe with UEFI) to this one. For some reason I don't exactly remember I tried to switch the computer to UEFI, but it didn't work out and I switched is back. That was around a year ago. Since then everything with the bootloader worked fine ... until last saturyday.