Found these inside a non-working 71B

[rprosperi]

(03-14-2018 02:17 AM)MikeSD Wrote:  After Destroy All", i get a slightly diff number, 82415. Any chance it has something to do with Math ROM. Repeated Init3 and MEM is consistently reporting 82427. Bu oddly, everytime I do Desroy All. it changes to 82415. Repeatable

Indeed, the manual confirms the MATH ROM allocates 43.5 bytes for internal use. It seems some of that is allocated for default variable storage, as the DESTROY ALL removes 22 bytes (82437 => 82415).

But this does not account for all of the missing RAM, it still seems like almost 1000 bytes is "missing". Perhaps there is some overhead required for the extra 64K System RAM.

Not directly related, but lets see how the 64K was allocated. Can you try FREE :PORT(0.04) and if it succeeds, then try MEM(0.04)? It should be just under 32KB. You can return the IRAM to SysRAM by CLAIM :PORT(0.04). The same process should also work for :PORT(0.05).