Hi @fcb5511,
I imagine you need to validate the a/b swap use case? There are various documents describing bootloader and firmware updates, but I think AN12323: S32K1xx Firmware updates explains it in a very detailed way, with an included demo app (for both S32K146 & S32K144).
I believe the use case you are referring to is located in chapter 6.1.1 & 6.1.2 (S32K144 Memory Map for A/B Swap, with single pflash block & S32K144 boot and update procedures).
You can read how to set up the demo on section 7.1, and the SW is available from the S32K1 documentation page (AN12323SW).
Hope this helps.
Best regards,
Julián