Crouton on sdcard

Using microsd card to run crouton

format microsdcard using chrome recovery utility

then mkfs.ext4 -t /dev/mmcblk0

then label using e2label /dev/mmcblk0 labelname

Download crouton to Downloads folder

copy crouton to /usr/local/bin

sudo mount -i -o remount,exec /home/chronos/user/

From Downloads folder type

sudo crouton -r buster -t core,cli-extra -p /media/removable/Crouton