Hi Oliveira,
Your mentioned SDK1.3.0 and the KDS is really very old now, if you are using the K64 SDK, I highly suggest you use our newest SDK which can be downloaded from this link:
https://mcuxpresso.nxp.com/
About the IDE, KDS is not updated now, and we are using MCUXpresso IDE to replace it, and the SDK is mainly based on the MCUXpresso IDE, IAR, MDK, etc.
You can download the MCUXpressso IDE from this link:
https://www.nxp.com/design/software/development-software/mcuxpresso-software-and-tools-/mcuxpresso-i...
So, please use the newest SDK, and the K64 SDK already have the flash project, you can test it directly, please don't use the old SDK 1.3.0 and the KDS.
About the PE, you also can use the MCUXPresso CFG tool to replace it, PE is also not updated anymore.
Now answer your other questions:
Is there any difference between MK64FN1M0 and MK64FX512 other than flash size? I mean, I read somewhere else that MK64FX512 does not have EEPROM and MK64FN1M0 has (or otherwise, I could misunderstood it)... Does that have anything to do with this read/write problem or there is something left to tweek into KDS/PE/code?
Answer: K64FX has the flexNVM, flexRAM, which can be used as EEPROM, but K64FN, don't have flexNVM, can't use the EEPROM. Please use the newest SDK code:
SDK_2.9.0_FRDM-K64F\boards\frdmk64f\driver_examples\flash\pflash
If you use MK64FX512, you also can download that SDK, then you can find the related driver in this SDK folder:SDK_2.9.0_FRDM-K64F\devices
Wish it helps you!
If you still have questions about it, please kindly let me know.
Best Regards,
Kerry