Nokia Lumia 520 Error: Unable to find bootable option !!

[MiRoOo]

Hello guys,,
how are you ?? .. hope you all fine ..

i have this Lumia 520 with weird problem ..
when i power on the phone it shows this error ..

Unable to find bootable option

this is what i tried so far ..

-Flashing with BEST with same Product ..

Device catched in BOOT mode!
Boot Mode confirmed!
Setting Preloder
Collect Info...
Setting Application
Setting Secure
Collect Info...
=== Nokia Flash App info :
Protocol Version : 1.15
Protocol Implementation : 1.28
=== Phone Initial info :
Phone RMxxx ID : RM-914
Phone Model ID : Nokia.MSM8227.P6036.1.2
Phone Model PC : 059S1L3
Phone IMEI : 355910057282023
=== eMMC info :
eMMC Vendor : Unknown
eMMC CID : 0090
eMMC Size : 7400 MiB
=== Security Initial info :
Security Status : 010100000101
Secure Boot : Enabled
Secure eFUSE : Enabled
JTAG : Disabled
RDC Key : Not Present (Retail)
UEFI SBoot : Enabled
SecHW Key : Exists
Device RootKey : F771E62AF89994064F77CD3BC16829503BDF9A3D
=== Other info :
SD present : False

FFU : RM914_3058.50000.1425.0001_RETAIL_im_mea3_333_01_4 44358_prd_signed.ffu
Checking...
Device RootKey Match with FFU RootKey!
Device ProductID Match with FFU ProductID!
ProductID :
DevRKH : F771E62AF89994064F77CD3BC16829503BDF9A3D
All Ok, Continue flashing...

FFU : RM914_3058.50000.1425.0001_RETAIL_im_mea3_333_01_4 44358_prd_signed.ffu
Flashing FFU
Sending FFU Header CertData
Header NOT ACCEPTED! Image Can't be flashed
Red Light
Error during flashing!
LastErr : 240000005061636B6167653A

-Recover with NSUR ..
After downloading the firmware and start installing it says ..

PHONE NOT SUPPORTED!!

-Flashing with other tools ..

FAILED

So, i need you help guys to fix this weird problem ..
also i want some info about this problem ..

thx in advance.

[Dzirt]

Hello. Need repair boot first (jtag) and flash phone after.