Hi @DiaDev
There is no direct application note for the S32K3XX devices as with the S32K1XX; However, there are some ANs and examples for FW updates:
Under the S32K3 HSE Demo Examples, there is the Secure boot & Device configuration examples, which showcase basic/advanced secure boot, HSE installation (FULL_MEM & AB SWAP), along with other functionalities.
There is also the OTA DEMO application which can be found in S32K3 Reference Software: SW32K3-REFSW-D.
Finally, you can also refer to the Unified bootloader Demo & the Example S32K312 Bootloader to Application Jump DS3.5 RTD300 from the community.
Hope this helps & best regards,
Julián