General question about recalls involving software flash?

[DM58]

With software updates such as 67a that claim to be irreversible, where does the information get flashed? And, if it is a replaceable unit such as PCM, can a truck be returned to pre software update status by replacing the memory?

 

[06 Dodge]

With software updates such as 67a that claim to be irreversible, where does the information get flashed? And, if it is a replaceable unit such as PCM, can a truck be returned to pre software update status by replacing the memory?

The flash is for the PCM, as I understand it unless your truck is tuned with after market programing there is no way to roll back the 67a flash.