Minimal wheezy install images for b3

[pbertra]

I upgraded to wheezy without any issue (revert to minimal then upgrade).

But today I wanted to upgrade to Jessie:
- I updated the u-boot and checked that the version is correctly updated
- reboot => ok
- I upgraded the kernel to 3.2
- reboot => OK and new version is confirmed
- I did the dist-upgrade => ok
- reboot => KO!

B3 not booting anymore The led stays purple

After a lot of debugging, I tried to boot the rescue image => OK
I tried to re-install => KO. Blinking purple led
I finally decided to revert the U-boot to the 3TB one and tried to re-install : OK!

Now I'm back to the initial image

What did I miss? What did I have to revert the U-boot to make it work?

How can I upgrade successfully to jessie now?