A510F write cert error

[foony]

I can read cert, read efs, write efs but can not write cert.

Operation: Write CERT
Selected model: SM-A510F
Software version: 26.2

Waiting ADB device... OK
Reading phone info...
Model: SM-A510F
Android version: 5.1.1
Product code:
Phone version:
PDA version: A510FXXU2APC4
CSC version: A510FOXX2APC1
CSC country code:
CSC sales code:
HW version:
Phone S/N: R58H70FKR1Z
Modem board:
RF cal date:
IMEI:
Checking Super user right... true
Initializating zTool... OK
Running zTool, please wait...
Start... OK
Init... OK
Generate and check client proof... OK
Verify proof by client... OK
Reading data... error (8)

Done with Samsung Tool PRO v.26.2

any advice please?
thanks

[foony]

another try of writting cert

Waiting ADB device... OK
Reading phone info...
Model: SM-A510F
Android version: 5.1.1
Product code: SM-A510FZKAORX
Phone version: A510FXXU2APC4
PDA version: A510FXXU2APC4
CSC version: A510FOXX2APC1
CSC country code: Slovakia
CSC sales code: ORX
HW version: MP 0.200
Phone S/N: R58H12G89RX
Modem board: SHANNON310
RF cal date: 20160120
IMEI:
Checking Super user right... true
Initializating zTool... OK
Running zTool, please wait...
Start... OK
Init... OK
Generate and check client proof... OK
Verify proof by client... OK
Reading data... OK
Checking certificate file... OK
KEY ID: 0120
Reading nv data... OK
Checking NV data... OK
Calculating... OK
Exception: Access violation at address 0040745C in module 'SamsungToolPRO.exe'. Read of address 0A6D1000

[Z3X]

1. downgrade modem version
2. attach your nv_data backup here

[fedex89]

how do you downgrade the modem? thank you

[foony]

after downgrade modem same errors

[fedex89]

ok.. my a5 is 2016 version and have 5.1.1 firmware... but z3x box dont write cert :-(