I even partitioned the first partition to 4gb
The boot partition must reside entirely inside the first 4GB of the drive. This includes the first two cylinders which cannot be partitioned. Also the display in HDToolbox is rounded. So if it displays 4GB it is anywhere between 3.5 and 4.4 GB. A single byte above the 4GB border causes your crashes.
Make the boot partition 500MB or 1GB. This is plenty of space and does not give you any problems.
The "boot loader" you mentioned is the AmigaOS ROM Update. It is loaded by SetPatch and installed resident in memory. Once it is loaded the entire HDD can be seen. But until then (from power-on to the call of SetPatch) all data to be read has to be accessible by the Kickstart ROM driver.
Bye,
Thomas
