Little issue with unlocked bootloader. Someone have this?

[Guest davidevinavil]

Sometime ago I succesfully unlocked bootloader.

This mean that I could flash boot or recovery with fastboot:

fastboot -i 0x0502 flash boot boot.img

Then I upgrade to AV051_S500_1.056.00_WW_GEN1 and got this error

sending 'boot' (6306 KB)... OKAY

writing 'boot'... FAILED (remote: Due to device is fused, non-merged file is not supported)

luckily I'm still able to flash boot with CWM, so I'm here to ask you if notice this thing...

[Guest rjscosta]

Is there a method to unlock the bootloader without downgrading to the JB leak?

Something like flashing just the bootloader on CWM, leaving the rest intact?