Lpc2000

I'm unable to "syncronize" with the boot loader via hyperterm on
windows or minicom on linux.  I know that the serial/USB port actually
works because I'm running a modified version of Olimex's uart_echo on
the board.  And, the Philip's ISP utility can do it.  But, I'm trying
to get some of the Linux alternatives (like lpc21isp) to work and they
don't.  My understanding is that typing a '?' to the board when it is
jumpered in ISP mode will get the on-board firmware to respond
"Syncronized".  It doesn't.  I get no response at all.  lpc21isp
doesn't get one either.

Am I missing something?  Any ideas for me to try?

Thanks,
Eric