Hi@Joseph_David
I list all the info that we have for your reference, you can serach these document and demo in www.nxp.com.
1.AN12323: S32K1xx Firmware updates – Application Note
Senlent_1-1748328356023.png
2.AN12218: S32K1xx Bootloader – Application Note
Senlent_2-1748328452290.png
3.AN12003: Using S32K148 FlexNVM Memory – Application Note
Senlent_3-1748328595213.png