S Lafredo> real-base     -1      <- default

real-base may not be changed until you get kernel-loading-stop
like:
--------------
0 > boot ata/ata-disk@0:0 
>> NetBSD/macppc OpenFirmware Boot, Revision 1.2
>> (matt@duel.local, Sat Aug 18 13:46:09 PDT 2001)
2931820+237444 [100+106512|
(no response at this point)
--------------

S Lafredo> Using the OF prompt I have also tried...

S Lafredo> boot ata0:0,netbsdboot ata0:0,/netbsd
S Lafredo> boot ata0:0,NETBSD
S Lafredo> boot ata0:8,netbsd
S Lafredo> boot ata0:13,netbsd

how about just
boot ata0/ata-disk@0:0

or what is show at OF command level,
dev ata0
ls ?

mine (OF 2.02,StarMax) shows
0 > dev ata  ok
0 > ls 
FF839628: /ata-disk@0,0
 ok

---
Makoto Fujiwara
http://www.ki.nu/software/NetBSD/iBook2/