Main and patch has to be the same, if you read the instructions, It clearly states that to apply the patch you need the vkp patch and the firmware to be flashed to add in the right panel
-IMPORTANT INSTRUCTIONS:
select any db2020 model
press identify, note yours firmware version
get that firmware and add it to firmware area with "add" button
check "Bypass DB2020 security"
add text file with setool2 script command or .VKP script
press flash.