WIZ750SR-110 GCC?

Has anyone had success building the reference app for the WIZ750-1xx devices with GCC? It is too large for the free Keil linker. I can get it to compile and link, but it does not work. To clarify, I am trying to use uVision 4 or 5 with GCC tools in place of Keil.
OK, tried the Eclipse project too. Same result, builds but does not run.

Got demo license for Keil, and that works as expected.

Is the problem solved?
The source is aware that the Keil version sometimes determines the behavior.

No, it is not.

I suspect that the memory configuration is the problem, but I have not figured it out yet since that involves learning two new assembler syntaxes.