Pegwilson

Sorry it took me so long to try your method - a combination of lack of courage and acquisition of a little Garmin replacement (for $120 at Costco). Anyways, finally got around to it and it worked perfectly. Thanks so much for the detailed instructions. I also took the update disc back to the dealer who refunded my $300, and suggested that I contact customer relations and tell them what a lousy piece of software it was.

Man...that sucks that they want to work you like that. You will be especially annoyed when you see how easy it is. The links above by dadcat work great for instructions, but there is a RX specific one so I will attach it here, too. RXNavi_1_.pdf When upgrading, you simply place the disc in the drive and it updates. Easy. One thing you will need to do differently in order to "downgrade" from the 8.1 to your old version is to reset the system. In my 2006 RX400h you have to pull a fuse to get the system to reset. Under the hood on the driver side, you will need to remove the two trim covers, and then look for the square fuse box. In the lid of that box is a white fuse puller. Use that tool to pull the Radio1 fuse for about 2 minutes. You will know you have the right fuse if the nav system stays blank with the key in the "on" position. So here are the steps: 1. Open up the tool compartment in the back following the instructions provided. 2. With the ignition in the "on" (do not start the vehicle) open the drive door and pull the disc if there is one. 3. Put your old disc in the drive and slide the door closed. 4. The Nav screen will say something similar to "put the correct disc in the drive" 5. Turn the ignition off. 6. Pull the Radio1 fuse and turn ignition to "on" no need to start it. 7. verify that the nav screen is not displaying anything. 8. Wait about 2 minutes (only really takes about 5 seconds to reset, but wait just to be sure) 9. Turn off the ignition and replace fuse. 10. Turn ignition to on and wait for the "Loading" screen. 11. Select your default search region and you should be ready to go. Let us know if you have problems with the downgrade process or if you need more info on making a hybrid disc. Good Luck!

I had the dealer install the latest version of the Nav DVD in my 2006 Lexus before I checked with the Forum and found out that I was losing the over-ride. I still have the old DVD - but the dealer wants another $100 to reinstall it (adding insult to injury). Is it possible to re-install the old disk myself? If so, how would I go about doing it (detailed directions appreciated) - and will I get the over-ride function back?

Sadly, the Gen 4 Navigation system loses the ability to use a hybrid disc after version 6.1. The reason for this is because Denso restructured the file system for Gen 4 on version 7.1, therefore the old 5.1 LOADING.KWI file no longer references the correct files. This has been the holy grail of Gen 4 nav hacking, and so far it has eluded the efforts to crack it. A hybrid disc can be made with 6.1 data, and replacing the LOADING.KWI file with the one from 5.1 or earlier. Personally, I use a 5.1/6.1 hybrid disc and it works just as it should: 6.1 POI and map data, 5.1 OS that allows the bypass. Sorry for the bad news on this issue.