Hi @zephyro,
As mentioned in this anouncement, Mbed TLS is now maintained under open governance at TrustedFirmware.org.
I would suggest you post your question there, as it doesn’t seem your question is Pelion related.
Your issue seems to be some platform related issue.
Could it be that the memory in segment A uses physical memory, and in segment B uses virtual memory?
Could it be a caching issue?
Regards,
Mbed Support
Ron