Down grade LG Firmware

[BLURAYJAKE]

I'm having trouble downgrading my drive from 1.05 to 1.02, Dled LG Crossflash NS50 firmware pack but program states checksum is mismatched. I dont have the funds to get my drive to rip 4K so I'm trying all Aves

Drive Information
OS device name: F:
Manufacturer: HL-DT-ST
Product: BD-RE WH16NS40
Revision: 1.05
Serial number: KLBK9MJ0603
Firmware date: 2120-05-06 14:40
Bus encryption flags: 17

LibreDrive Information
Status: Possible (with patched firmware)
Drive platform: MT1959
Harware support: Yes
Firmware support: No
Firmware type: Original (patched version available)
Firmware version: 1.05
DVD all regions: Possible (with patched firmware)
BD raw data read: Possible (with patched firmware)
BD raw metadata read: Possible (with patched firmware)
Unrestricted read speed: Possible (with patched firmware)

[Billycar11]

read guide below not some youtube video from 2-4 years ago i keep this updated