Prolific PL-3507 Hi-Speed USB & IEEE 1394 Combo to IDE Bridge Controller

I have a generic USB2/IEEE1394 (Firewire) external hard drive enclosure. It is built on the Prolific PL-3507 Hi-Speed USB & IEEE 1394 Combo to IDE Bridge Controller; this is a record of my recent troubles with it.
Currently it house’s a Maxtor 6 Y130M0 (120Gb) Hard Drive. I’ve found it to be totally unreliable over the firewire interface and only just bearable over the USB interface. The enclosure itself isn’t by any brand and there is no direct customer support for it. I found the following pages while googling.
http://missig.org/julian/blog/2004/06/10/prolific-pl3507…
http://championable.com/2005/01/avoid-prolific-pl3507-chip…
http://www.hollants.com/external_usb_controller_chips.html
http://www.alexking.org/blog/wp-mobile.php?p=1152&more=1
I followed the general advice and downloaded the firmware and various versions of the Flash Utility from:
http://member.newsguy.com/~siccos/PL3507%20Firmware.htm
Basically none of them worked. I used ROMWriter2.0.4.exe and tried the earliest firmware I found: PL3507-0907B.hex. This would go through “Erasing…”, “Writing ROM code…”, “Reading code from ROM…” then would fail with “ROM code verification error.”. I used this version of the tool to successfully copy the firmware off the chip, then re-write it to the chip without problems. I just cant get newer firmware to work.
Currently the chip is on firmware “2003.06.19.241”. I have tried all versions of the Flashing Utility I can find against all versions of the firmware I can find.
Unfortunately this chip appears to be widely used, I was about to buy a replacement enclosure when I found that all of them were using the PL3507 chip.
Next Stop, contacting Prolific
Update: 28th December 2005 – Six months later and Prolific never did reply, in the end I threw away the old enclosure as it was no longer needed. Shame.