AT command interface works! The cause of the breakage was the same Nucleus API issue with NU_Create_Timer() which we encountered at the very beginning of this project with Riviera timers: the code in uartfax.c from TCS211 was passing 0 as the initial dummy value for the timer duration, and our FreeNucleus version doesn't like it. The fix is the same: pass 1 as the initial dummy value instead.

s,^CC=.*$,CC=	/opt/arm-2012.03/bin/arm-none-linux-gnueabi-gcc,
s,^CFLAGS=.*$,CFLAGS=	-O2 -march=armv4t -mtune=arm920t -DGTA0x_AP_BUILD,
s,^EXTRA_OBJ=.*$,EXTRA_OBJ=	compaldummy.o gtapower.o,