Raspberry Pi doesn't boot after update

[matthme]

In an attempt to get a raspbian image with software that is not massively outdated, I have changed the "/etc/apt/sources.list" from "wheezy" to "jessie", and then run "apt-get dist-upgrade". On both Google Coder v0.6 and the latest Raspbian Wheezy from the website (2014-06-20-wheezy-raspbian.zip), it updates fine (takes several days ) but then it refuses to boot. It boots fine before the update, and the SD card is not to blame, and there is no overclocking.
It starts to boot, says "Welcome to Raspbian GNU/Linux jessie/sid", then something about systemd, and then it stops. No green light, no keyboard response. Rebooting does not change this.
Adding "init=/bin/bash" to the cmdline.txt file gives a root terminal that responds to the keyboard, but it does not work as a normal terminal should.

I would post a photo of the screen but it won't upload and since it's on my computer, a URL is useless.

I have tried the wheezy => jessie upgrade with Debian amd64 on my laptop and it worked fine there.

[morgad]

I have a photo too, but it is over 64Kb

I have struggled with this for last four weeks ...
backup the card first if you can, so you can revert if changes cause more problems

I had "need_statd=yes" in /etc/default/nfs-common
reverting this to "need_statd=" helped

I got around 1 in 10 boots succededing, and no idea why!
on one succesful boot 2 days' ago, I apt-get upgraded, and rpi-updated which seemed to help boot reliablity
when I did this I tried to accept the maintainers versions of the config files when they differed
(answered D for diff, then Y to overwrite, where I would normally would enter N)

I was also getting problems with the network not coming up,
adding the missing "auto eth0" to /etc/network/interfaces fixed that

still not sure if nfs/samba/gpsd are working yet ... still backing up the SD card (32Gb)

best regards
Dave