I've been trying for several days now to get jtag-0.6 to correctly detect the IDCODE on an LH7A400. I have been able to use JtagIO to read the ID code on this and other identical boards without difficulties.
Here is some output:
jtag> cable parallel 0x378 WIGGLER
Initializing Macraigor Wiggler JTAG Cable on parallel port at 0x378
jtag> detect
IR length: 4
Chain length: 1
Device Id...
2007-11-07 06:30:58 UTC in The openwince project