Historically when an un-linked AutoCal device performed its first controller flash, it would automatically link itself to the Master FlashScan device that created the file being flashed, thereby linking itself to that master FlashScan. That automatic linking is no longer supported and will not occur under any circumstances.
EFILive has replaced this process with a new [Generate Remote-Link Code] option managed in the same location as the Physical Link AutoCal process in the EFILive Control Panel -> [F7: Licensing] menu.
Prior to reading or flashing any controller, the EFILive software performs a security negotiation with the controller for permission to access the controller. In the past, the security negotiations were implemented using a simple challenge-response process.
In 2017 GM began modernizing and hardening their controllers' security negotiations which is now far more complex and virtually impossible to automate within the EFILive software. This means the end user must now concern themselves with the security negotiations prior to reading or flashing one of these new controllers.