How to pair Firefox 29 with Owncloud's mozilla_sync / Weave

gistfile1.txt

_Go to your Owncloud installation <https://myowncloud/remote.php/mozilla_sync> and accept the SSL Certificate
_Open about:config
_Create: services.sync.username <string> the value should be a hash not the username itself. (You only need the hash if the
sync was setup with a pre FF29, if you start from scratch the string doesn't matter)
You can look this up in an older browser or in the logs of your Owncloud server!!
_Go to: Preferences -> Sync -> Setup Firefox sync (you should see the old UI now)
  'I Have an Account'
  'I don't have the device with me'

  'Account' - again use the hash NOT the actual username!
  'Password' - ...
  'Server'  - https://myowncloud/remote.php/mozilla_sync/
  'Recovery Key' - Get the right key from an older browser, you can find it in the sync settings

If nothing happens on the 'Next' button, restart your browser and start over.

This is broken on FF35. I have tried to set up a new account. Get to a window where I can enter the email adress, the password and the server. I have to answer a captcha question, too. But no luck. The 'next' button is always greyed out. I have no old hash or whatever. Setting services.sync.username to some string enables the old sync interface once. After reaching and leaving this interface, the old one pops up again and services.sync.username is empty.

In FF36, MegaVolt's suggestion for starting from scratch no longer works. The instructions say to use the hash instead of the email address, but FF now validates the format and says that the account is not a valid email address.

In my FF 36.0.4 the account setup hangs during the account verification without any error message.

EDIT: fixed, a couple of firefox restarts fixed that.

Sync continues to work with Firefox ESR 45.7.0, and I just tested the above instructions against SeaMonkey 2.46. Happily, still works fine!