Some update, I can still put the phone in fastboot mode, and I was almost ready to flash Sailfish images. But again, the bug having locked the bootloader prevents it:
./fastboot oem unlock
FAILED (remote: ‘access denied. need privilege!’)
fastboot: error: Command failed
./fastboot flash boot boot.img
Sending ‘boot’ (8808 KB) OKAY [ 0.553s]
Writing ‘boot’ FAILED (remote: ‘access denied. need privilege!’)
fastboot: error: Command failed
If anyone is having a hack to bypass this, I take advices.