Fastboot error FAILED (remote: Partition flashing is not allowed)

Hi all,
I need to flash a new Android kernel on DragonBoard410c. How to unlock emmc ?

sudo fastboot flash boot out/target/product/db410c32_only/boot.img
target reported max download size of 268435456 bytes
sending ‘boot’ (11858 KB)…
OKAY [ 0.481s]
writing ‘boot’…
FAILED (remote: Partition flashing is not allowed)
finished. total time: 0.485s

First time I see this issue. Maybe you should follow EDL recovering step to recover the partition table: (use aosp recovery binariers)

@Loic Thanks for help. It’s working after recovery.

sending ‘boot’ (11858 KB)…
OKAY [ 0.488s]
writing ‘boot’…
OKAY [ 0.904s]
finished. total time: 1.393s