A bit of WARNING HERE, READ:
1) I am not sure what is the result with multiple devices on the same account
2) I am not claiming this solution will work with all android devices, I said in the video “it SHOULD”. As you can read in the comments, 99% are claming that this procedure is indeed working.
3) You can try this but at your own risq. As you can see in this video, it did work fine for me. I had to redo this procedure once again during the course of 2012 when I had to reboot my phone again for other reasons and it still had good results.
4) I am not sure all version of Android will have the same results. The results you see in this video are with Android Gingerbread 2.3.2 and as of 2013, my phone is still on that version.
So, if you are stuck with only one month back in time with your google calendar or agenda in your android device, you might give this a try.
There are two way you can sync google agenda past events for more than one month back in time.
1) You can manually edit one or many events and it will show back up on your android device. Simply add a single character (like a single dot “.”) in the event description and it will sync back that event in your android device.
2) If you need this for all your events, you simply need to export your agendas and re-import them again in your google calendar/agenda personal page. This will sync all previous events of all your agendas on your android device.
Resync of 500 events took 3 minutes on my android device before I could see all the events back.
Leave comments on how success/fail/nothing happend you got and also maybe list your android device and version of OS.
EDIT May 2013: I have been receiving positive feedback from many users that claim the procedure worked good for them too. One confirming that it did worked with a 10 year old agenda with over 7000 events that has re-sync correctly to his mobile device GSIII.
Thanks for watching !