I am designing a product for which the Raspberry Pi is part of the system. It is basically used as the bridge for BLE sensors to communicate with cloud servers. Basically, each time my product is shipped, a pre-programmed Raspberry Pi is shipped as well. However, I need a way to physically identify each unit during production to be able to track which unit goes where and to whom, etc... This leads me to using a serial number. The problem is that to give or extract a serial number, we have to wait for the Rpi to boot, which can take up to 60 seconds when the desktop portion is activated. When you have 150 units in production, this can take a while to happen.
Anyone have a recommendation for a different approach or can confirm that my approach is the right one?