Because it had to be setup with MBR as the partion type I could never boot the HFS partition.
I am aware, that I cannot boot from the machine, once I use a FAT32 partition (and thus a MBR).
I used drive setup (in OS 9) for mine. Specified two partitions and the two types I wanted and then it worked.
I will try it again when I am at home after work today.
I doubt that you used Mac OS 9 Drive Setup, as it does not support formatting or partitioning of FW (or USB) drives.
It would be great if you can have a look at home how you exactly did it.
Here is what I tried again in the meantime: I formatted the drive again with gparted. Two FAT 32 partitions this time. These partitions get not mounted in Mac OS 9 with FireWire.
They took ages to get mounted in 10.4.11 - about 5 minutes.
So I decided to give it another try with 10.4.11 and hooked the HD up to the G5s USB.
Suddenly Drive Setup of X (Version 10.5.6) offered me "MS DOS" as partition option. So I formatted the drive again with MBR and one "HFS+" (BTW what is the difference here between "HFS+" and "HFS+ (Upper/Lower case)"?), and one FAT32 partition.
Hooked it up to the 9 machine, and no partition got mounted with FW, but the FAT32 with USB 1, ...
So I formatted the drive again with 10.4.11 but this time with 2 FAT32 partitions at the USB and checked at FW - worked. Now I got the same resoults at 9 with FW and USB. Always the first FAT32 partition was mounted but not the 2nd.
Subsequently I checked my 9 for any FW issues, and put all the HDST FW extensions off (the whole FireSCSI stuff) and turned iPod FW enabler on again, as the description only said "FW Mass Storage driver". But that didn´t change anything.
As I had the same USB and FW issues with 2 FAT32 devices, I don´t think it is connected to the 9 machine, but to the formatting that X does.