What kickstart version is it? i have found problems with 3.0 not seeing certain drives, not specifically dependant on size.
e.g. i tried 3 drives in a ks 3.0, 4.0,4.6,3.2, only the 4.6 was recognised.. Odd..
The other drives worked un ks3.1 on a diff 1200.
Some drives require pin 1 on the cable to be cut, then they don't reset with the amiga and stay on. soft reset upon power up before booting.