[Q] N9 stuck in fastboot, locked and unlockable topic

Hi all,
I tried to reflash a Nexus 9 with official volantis-lrx22c, the bootloader was updated (3.43.0.0114) but the flash of the other partitions failed and now the device can only boot fastboot mode in locked and unlockable state.
When I try to reflash:
(bootloader) Device State : Locked
FAILED (remote: Can not flash any images while device state is locked!)

And when I try to fastboot oem unlock, I get:
(bootloader) ability is 0
(bootloader) Permission denied for this command!

I cannot boot android, so I cannot enable the the "Enable oem unlock"

Before this, I could falsh a recovery and backup, but the recovery disappeared and I cant flash anything anymore...

Any solution? Any way to force the oem unlock or the flash?

I saw this guy, Jonathan Levin, (I cannot post the link) that checked the effects of this "Enable oem unlock" on PST partition and saw one bit was set after, I was wondering if I could use "fastboot oem i2cw" + correct parameters to flip the corresponding bit, but I dont know if it's possible and what are the parameters to pass...

Thanks,
Pierre