Hi all, I thought my chartplotter (2004/2005) had seen better days until I realized that after registering at their site, a bit late I know, it gave  me access to the very lastest Matrix 97 update d/load,  with the the unit not reading all of the detail in my Navionics Gold card I decided I had nothing to lose and go with the current update using the MMC/SD slot and it worked. Now seeing all the card detail and it added a new heading to part of the menu and changed something with the sounder too and gave more adjustment to the scroll speed. After setting the unit back to "Defaults setting" as instructed then powering down , powered up with the SD/update in the slot for successful update. It's like new again.
P/S Backup your Way-points first as I did lose mine but no problem as they where in HumminPC program, D/load to SD card and and into MMC/SD slot power-up and there they are back again. The main Humminbird D/load went straight from the desktop into the SD card to the 97 unit, no prob.

I hope this might help anyone thinking of doing the same.
Cheers again

Highly recommended......

http://www.humminbird.com/Support/ProductRegistration.aspx