Why the chip STM32F446RCT6 flash size is 512KB, not 256KB?

[llm]

I buy some chips marked STM32F446RCT6 which flash size should be 256KB.But when I connect it use STLINK, I found the real flash size is 512KB.I have save some data after the address 256KB successfully. And I can read out these data.Am I buy fake chips?

[Peter BENSCH]

Please have a look at this thread, where an unexpected flash size was also found.

It can therefore be a real STM32F446 if the other parameters are correct (e.g. Unique ID, etc).

Regards

/Peter

[Uwe Bonnes]

All chips with the same CHIPID are created equal. During test and packaging, some differentiation are may be applied, but the already produced flash is not physical remove but probably not tested and perhaps made inaccessible by some fuse.