STK-L21M after flash "Device has Failed verification"

Huawei STK-L21 was Frp with android 10 version. and i download the downgrade file 10.0.0(c185) for FRP from FTP server.
after full flash by A.O.D files my phone cannot run normally. its error on booting (Image).
then i try to flash stock firmware 10.0.0.197 (Last Security) with SD card. after successfully flashed i got same error.
again try to flash downgrade file AOD but this time flashing failed (Image)
if put fastboot mode and try to read-info i got...

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