If you didn't know, there's a new firmware release for E71 which is 400.21.013; you can check if you E71 model can be upgraded at this website: Nokia Software Update. You'll just need to enter your phone's product code (refer inside your phone at the simcard location for the code) to see if you can upgrade. Just follow the website's instructions.
I've upgraded mine and working great so far. :)
What i did for the upgrade is as follows:-
1. Backup my contacts, notes and calendar details using Nokia PC Suite and synchronized to Microsoft Outlook. This synchronizing thing i have done periodically and has been a great way for me to organize my contacts and notes.
2. Backup my messages using Nokia PC Suite's Content Copier. You can in fact skip the first step by using Nokia Content Copier to backup your messages, contacts, notes, calendars and others.
3. Backup my Garmin's locked locations (My Locations). I messed up this step by doing it wrongly and i've lost all my locked locations. The correct way should have been to access Garmin software: Garmin>Tools>Manage My Data>Manage>Export GPX. Thereafter exit the software and connect phone to PC, find the GPX folder inside the Garmin folder and copy that GPX Folder to your PC. POI Folder can also be copied to your PC if you have anything inside there.
4. Backup all documents (quickoffice and pdf files), songs, apps and others from the memory card to PC.
5. Formatted my memory card: Menu>Tools>Memory>Options>Format Memory Card. This is just to be sure to have a good clean state of the card and remove all unnecessary installation files (if any) prior to the upgrade.
6. Take note of your memory card password. If you did not set any password, take note of your REMOTE LOCK password. This has proven useful to me. :) You should also take note of softwares which require login or email activation such as quickoffice, worldmate, nimbuzz and others, note down the emails and login details used.
7. Hard Reset the phone via *#7370# and *#7780#. I did both. The 3 finger salute method (Y+U+Green Call button and turn on phone) would have been better i suppose but i forgot the keys and lazy to find it at the time.
8. FINALLY UPGRADE THE FIRMWARE. Just follow the instructions from the NSU site or here as it basically instructs you to download a software (Nokia Software Updater) almost like the Nokia PC Suite for the upgrade. Be sure to have a good and steady internet connection during the upgrade and the phone's battery is more than half as it will take about 30minutes to 1hour for the upgrade (depend on internet connection) as you'll need to download approximately 100MB++ worth of upgrade files.
9. After the upgrade is done, restart your phone.
10. You'll be asked for memory card password. Just enter the REMOTE LOCK password.
11. Copy back all documents, songs and apps to the memory card.
12. Restore/Synchronize contacts, messages, notes and calendars using Nokia PC Suite (Microsoft Outlook or Nokia Content Copier)
13. Reinstall all apps (including Garmin). Note that for certain softwares, you may need to change the date to a few years back as you may get "certificate expired" error when re-installing the apps. This process will be tedious so hang in there :)
14. Copy GPX folder into Garmin folder inside memory card.
15. Open Garmin software: Garmin>Tools>Manage My Data>Manage>Import GPX. This will restore all the previous locked locations.
Let me know your experience. Good luck and all the best.