Installation overwrites USB boot stick

[Michael Klein]

We are currently using an USB stick with autodiscover functionality.

Occasionally, the installation (Debian bookworm) goes to the USB stick 
instead of the internal disk.

This is from fai-disk-info:

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
checkdisk() {

     while read major minor blocks device suffix; do
         isdisk=1
         # skip ide cdrom
         [ -f /proc/ide/$device/media ] && grep -q cdrom 
/proc/ide/$device/media && isdisk=0
# old way of detecting disks: [ `cat /sys/block/$device/removable` -eq 1 
] && isdisk=0
         [ `stat -c %G /dev/$device` = "disk" ] || isdisk=0


During the installation, both the USB stick and the internal SSD is 
owned by root:disk, so the USB stick is not skipped here.

As expected, /sys/block/sd*/removable reads '1' for the USB stick and 
'0' for the SSD.

What is the advantage of checking the device group instead of the 
removable flag in /sys here anyway?

/Michael