ecos on lpc2378, context swtitching

[Sartakoff A. Wasiliy]

Hi. 
I have some problem with porting ecos on lpc2378. 
i have a good worked redboot on lpc2210, and i try start it on new platform.
i changed platform_setup.h pll init, some correct UART and timer, and redboot 
started on lpc2378. z-modem works too.  but when i use "go 0" or something 
else, i havnt context swtiching. good idea for looking on stack, but stack 
placed in data segment, and i havnt problem with it. my chip rev. B(Y?), and 
i use MAMRC 1, just in case. 
can u help me? =)