>> it was lifted even earlier with the Quicksilver 2002 models.

> this limit has been removed with Quicksilver

Quicksilver 2002, as I wrote. The original Quicksilver from 2001 was the last PowerMac to have this problem.

> some macMini users encounters problems when upgrading their machines with
> new bigger Hard Disks...

Any links? (We seem to go round in circles.)

> Could it be [...] incompatibility with some families of Hard Disks electronics that causes
> the fault.

There is always the odd chance that a certain HDD or even entire HDD family and a certain controller don't work together even when they should. I've yet to come across such reports regarding the on-board PATA controller of the Mac mini G4, though.

> I read Western Digital 320, and Samsung are more prone not being recognized.

The third one of my three links in comment #16 is to a thread where two users report the Western Digital 320 GB 2.5" PATA HDD (Scorpio Blue WD3200BEVE) to work flawlessly in their Mac mini G4.

> almost all 3,5" and 2,5" IDE Hard Disks of big dimensions still on the market are right from
> Western Digital.

Of the eight 320+ GB PATA HDDs listed by Heise Preisvergleich, four are from Western Digital and four from other vendors (Seagate, Samsung, Hitachi).

> As long as none was capable to answer me.

You're kidding me, right?

> I decided to buy a 320GB IDE 2,5" and test myself, and being a guinea pig for the sake
> of the MorphOS platform.

Huh? As can be read from the third link in comment #16, several MorphOS users have been using this very HDD for years successfully. How does that make you a guinea pig?

> If I encounter any 128GB issue I will report in this thread.

I'm looking forward to never read from you again in this thread ;-)