[Q] Help my phone are brick

Help me please . I have bricked my phone, I've been usin cm12 and once I rebooted and it was bricked. :crying:
It just boots in bootloader with the next code:

failed to validate boot image
Fastboot Reason: Fall-through from normal boot mode
I've tried to restore firmware to unbrick it but I can´t and I'm sure that I'm using a compatible firmware (for XT1511).

I have the following problems:

Code:

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mfastboot oem fb_mode_set

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returns

Code:

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FAILED (remote failure)

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then

Code:

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mfastboot flash partition gpt.bin

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returns

Code:

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target max-sparse-size: 256MB
sending 'partition' (32 KB)...
OKAY [  0.032s]
writing 'partition'...
(bootloader) This may take a few seconds, if a
(bootloader) different partition table is being
(bootloader) flashed since we need to backup
(bootloader) and restore a few partitions
(bootloader) Flashing primary GPT image...
(bootloader) Failed to write primary GPT.

(bootloader) Failed to program partition table
FAILED (remote failure)

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So everything else fail to flash
I have tried with different firware but all is tthe same
Pls help me :(