Tektronix TLA704, installing large disk drive

[CambridgeMart]

I have a TLA704 which I am upgrading to Windows 98SE and system software version 3.2. Whilst at it, I wanted to fit a larger disk drive; the smallest I have is 30GB. In theory, I can use this provided I have a disk overlay installed. However, that's where I have a problem, with the drive installed and set to maximum capacity the BIOS supports and with LBA mode enabled, the analyser starts booting from the floppy but stops half way and appears to have crashed (won't response to CTRL-ALT-DEL and the Caps lock key is unresponsive). If I leave the drive connected but set the CMOS setting for the primary master to NONE, it boots fine.
Am I chasing a dead end trying to use a drive larger than 8.4GB?