Some time ago, Debian has finally been adopted officially by HP as a supported Operating System. They even have released packages for Sarge for it.
Of course, in the meantime, Etch is the new stable of Debian, thus, I had to revert back to the old tweaking ways, described at http://debian.catsanddogs.com/. On the various DL380 G5's I've worked with, this went very smoothly, and it runs perfectly. On the ML350 G5, it's something else...

The machine is a new ML350 G5, with a dual-core Xeon 5120. The system runs Etch AMD64 (stable), and everything seems to be in order. Installation of the agents went flawlessly either (with a bit of script tweaking to make up for the version difference).

The agents start up fine, and work properly, but unfortunately, a bit too good: once the hpasmlited is running, it triggers a system reboot. The syslog revealed the reason:

May  2 14:38:31 pbxcalpam hpasmlited[9887]: CRITICAL: System Fan Removed (Fan 6, Location CPU)
May  2 14:38:31 pbxcalpam hpasmlited[9887]: A System Reboot has been requested by the management processor in 60 seconds.

The thing is, it's very normal that Fan 6 (covering the second CPU socket) is not present, because there is no second CPU installed. I updated the BIOS to the latest version (as apparently, there was a newer version), but to no result.
My guess is that the agents inadvertently see the second core (it's a dual-core after all) as a new CPU, and thus detects a missing fan, covering the core.

Guess I'll have to log a call to HP. To be continued...