Hi Joel
This is just a guess, but maybe you haven't enabled backdoor access to the SRAM? (Note: I am not an expert on this stuff, so this may be unhelpful...).
Presumably the main processor core can see the SRAM OK. This is because you have configured the RAMBAR register in your start-up code. However, this does NOT mean that other on-chip peripherals like DMA and FEC can access the SRAM too.
What you need to do is enable the backdoor SRAM access using one of the configuration registers in the System Control Module (SCM). Confusingly, this is also called RAMBAR but it is unrelated to the main RAMBAR register.You need to configure this register and set the BDE (back door enable) bit.
To quote from the MCF5271 manual:
"Do not confuse this [main] RAMBAR with the SCM RAMBAR in
Section 11.2.1.2, “Memory Base Address Register (RAMBAR).”
Although similar, this core RAMBAR enables core access to the
SRAM memory, while the SCM RAMBAR enables peripheral (e.g.
DMA and FEC) access to the SRAM".
Hope this helps
Simon