Hi Paul,
unfortunately the Kinetis K22 processors naming is not straightforward:
Kinetis K 22: 120MHz (128/256/512 KB) = MK22FN128xxx12, MK22FN256xxx12, MK22FN512xxx12
Kinetis K 22: 120MHz (1MB & FlexNVM) = MK22FN1M0Axxx12, MK22FN1M0xxx12, MK22FX512Axxx12, MK22FX512xxx12
I.e. the MK22FX512Axxx12 and MK22FX512xxx12 are actually part of the 1MB & FlexNVM product line and are not supported by Peripherals tool.
I'm sorry for the confusion, we will update the release notes to be more clear about which K22 parts were added to the Peripherals tool.
Regards,
Lukas