The earlier raw dd of the Flex recovery image left the installer layout
(2MB ROOT-B placeholder, fixed 6GB STATE), so Flex booted as live media
and couldn't A/B update. The script runs the image's own chromeos-install
against the eMMC from neon, chrooted into the image in a private mount
namespace with all other disks masked. Handles the cros_efi cmdline
requirement, udisks auto-mount interference, and unreliable exit status.
Tested end to end on hp-chell.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
