Help with boot on sparc with 10.1

[sparc at hacknplay.org]

HI

i have a sunblade 1500 and want to install Release 10.1 , downloaded and burned this iso to cd . ftp://ftp.freebsd.org/pub/FreeBSD/releases/ISO-IMAGES/10.1/FreeBSD-10.1-RELEASE-sparc64-disc1.iso.

But it wont boot from this cdrom
so i download a debian sparc iso and test it with same parameteres , its booting. 

My question is: do i need the bootonly or is somethink wrong with my CD , maybe i use the wrong parameters for openboot ?

Greetings Markus