I know a few people here have been asking about converting the 2010 RNS-E from EU to US, so I thought I would do a quick guide. Took me a few coasters and some dumb luck to figure evertyhing out so hopefully I save people some time. I will be adding pics as I finish the retrofit but thought I would write everything down while it's still fresh.

Background: I have a 2007 A4 w/ Symphony II+. If you have the Symphony II+ you will have a quadlock connector behind the stereo, so you will not need a harness. Anything older, (e.g Symphony II, the tape deck model) will require the retrofit harness available on kufatec or elsewhere.

To begin, remove the old stereo.

If you are using Symphony II+, you will need to move a pin from the quadlock connector. The quadlock connector has 3 harnesses attached to it. Remove C and B (C should be green and B should be blue). There's a little black pin holding them in place. Gently push down with a screwdriver and slide out the connector.

Find pin C7. Use the label on the radio to identify it. Each corner of the connector will also have a number to help you identify pins. To remove the pin, simply tug firmly and it should come loose (though there might be a better way..) Then take that pin and insert it into B5 in the blue connector.

If you do not have a Symphony II+, simply connect your harness to the three connectors.

Install your GPS antenna. There are DIYs on here already for how to do this. You can connect behind the dash or if you're feeling bored, connect an extension into the sharkfin antenna.

Connect your radio antenna.

Finally, power on the unit and it should load. Enter engineering mode. First, press the NAV button. Then press and hold the top-left corner button (there are 4 buttons around a dial). Hold for ten seconds. Let go, and press and hold the top-right corner button until the engineering mode appears. Go to General > Version and you will see some numbers.

Write down the following: (I give example numbers below)
SW: 0200
HW: H07
HU/Nav SW Version:5741020
Boot: 574100B
Audio: 5740022 021209

Now, go home and find your RNS-E navigation DVD. You need a fairly recent one with the 575 folder on it. Copy the following files from the DVD to a folder on your desktop:
1. Sub-folder 575 (including LDM.BIN)
2. 00.VNS
3. 575INDEX.TXT
4. A575????.MOT <--the numbers after 575 will be different depending on the unit.
5. INDEX.TXT
6. LOADING.KWI

Using notepad, open 575INDEX.TXT
Change the number after SOFIDX to 10 more than your SW number from Engineering mode. In our example, it will be 210.
Change the 575 in NAVVER to 574. This tricks the unit into accepting an American (575) disk because we're telling it it's a European one (574). You also want to change the last 2 digits of the NAVVER so that they are 10 higher than your unit. So in our example, it will be changed to 5741030
Change AUDVER so that the first three digits are 574.
Save the file.

Use a hex editor (there are many free ones available, HxD is a good one) to change the following files. The left code is the address where you are making the change. The right is the text that should appear. Do not use find / replace because you may replace codes that do not need to be changed. You only need to change the code at the addresses below.

00.VNS
000001d0h: V57401 1030 (the 1030 should match the last four digits of NAVVER from the 575INDEX file
00000210h: V574

LOADING.KWI
00000050h: V574
00000080h: 1030 (again, this should match the last four digits from 575INDEX)
00000190h: V574

LDM.BIN in 575 subfolder
00000000h: .LDR V5740000

Burn this to a CD, finalize the CD, make sure no multisession is selected. Insert the CD into the unit and it will begin a software update automatically. No need to use vagcom to change any coding yet. Mine took about 10 minutes with a few reboots

At this point, you can begin using your navigation DVD. If you are burning one, make sure you use a DVD+R. If you have access to vagcom, then go to Navigation, change adaption channel 97 to 1, close vagcom, and insert a normal, unmodified nav dvd and the update should begin again. This will force the unit to update to a fully US version, instead of the hybridized version.

I have not yet received my faceplate, but will be updating this DIY once I do.

Any questions feel free to PM me and I will try my best to help. Note, I made this same statement previously and had a ton of people emailing me asking me to do all the heavy lifting for them. PLEASE read this, try the instructions, and if you fail, then ask for help!

Common Problems I've Noticed
I insert the CD and I do not see software update on screen.
Make sure you burnt the CD and finalized it. If it isn't burned properly the unit will not recognize the CD as a software update

I insert the CD and I see software update but nothing happens.
If the unit does not update on its own, then you did not copy the correct files, or you do not increase the count by 10 in the 575index file. Make sure you followed all these instructions.

I can't access my unit using VAGCOM. I get 'no response from controller' when trying to access Navigation
Make sure you moved the C7 pin to B5 if you had a Symphony II+ unit.