OK, but this is only a thing of the backup-destination - and should be checked anyway.
I am more interested if TitaniumBackup will be confused about the PartitionLayout when restoring SMS/Apps/Settings?
But since this programm is also intended to move data and settings from one phone to another, I think it should manage this - any comments? Anybody already tried?
I just had the same thought. I guess it will work.
@humorkritik seems to know much about Titanium Backup, maybe he knows more about how it actually works? Otherwize someone will have to try it for us to know more about this.
I think this might indeed cause some issues.
NB, I would definitely not fall into the category “knows much about” in case of TitaniumBackup! I’m a total newbie to Android, and to TitaniumBackup. But of course I had a look at that that when moving to a unified partition.
Short answer to the title question: yes, TB can restore your stuff after a unified storage update.
Long answer: I did that, and it worked. I remember some hiccups, but can’t remember specifics. (Damn it, I should have documented this as a tutorial. Thinking about doing that when I upgrade from 1.6. to 1.8.5 for my bitter-sweet caffeine boost.) Anyway, I still have the first text messages received with my FP, dating to Feb. 2014, in the Messages app. I later replaced this app by TextSecure, which completely bypasses the Messages app and stores the texts in an encrypted database (and can be used as a messenger similar to Threema, but being open source \o/ and less intuitive /o\ than the latter). This app also retained it’s complete messaging history after restoring with TitaniumBackup.
FTR, since I had to change my mainboard, and re-run the unified storage update, this should be of particular interest for people who want to switch to other phones - or from another phone to a Fairphone. 
Also FTR, I still find the backup/restore process with TitaniumBackup a bit… unintuitive, lest to say: clunky. And up until now, I could not get the “update.zip” solution of TitaniumBackup Pro up and running, which would allow you to restore the app itself without access to the Google Play store (which would be really great after an update, because I would not even have to look up my not-onscreen-keyboard-friendly WiFi PW, and could do all the restoring e.g. on a boring and long train ride).
Last, but not least, I would always suggest to do multiple backups with different offered solutions. Don’t put all your eggs in one basket - it’s better safe than sorry. (Oi, that’s enough proverbial safety lines for one day, isn’t it?)
Hi, I did a full backup with Titanium Backup on Fairphone 1.8 without unified storage to a second sd-card. Then flashed my phone back to 1.6, let the Fairphone Updater do his work to 1.8.5 with unified storage and installation of google play store. Then I installed Titanium Backup from Play Store and started the restore of all all system and user data.
I had no problems. Everything works fine. I just had to activate the sync of all my accounts manually.
Cool to hear, that this worked for you!
Did you (backup) and restore ALL user + system data (as TitaniumBackup provides as a batch process)?
If not, could you provide a list, which of the system data you could restore without any problems?
Most important (for me): all your SMS/Contacts/CallLogs/Accounts/Calender and App-Data could be restored successfully? All system settings (Alarms/Homescreen/ring tone settings) as well?
Cheers, Robert
@therob: Yes, I did a backup and a restore of ALL user + system data. The CallLogs and Accounts (CalDAV, CardDAV, Microsoft Exchange, DropBox, Google, Threema) are restored correctly. But I can’t assure You that SMS/Contacts etc. has been restore, because I use TextSecure as my SMS-App and an alternative provider to synch my Calender and Contacts, not the android (google) standard. For TextSecure (and all the other apps), everything worked well.
My calender and contacts are fine to, but I can’t tell You, if it is caused by sych again or caused by TitaniumBackup. Sorry, didn’t made that kind of check.
@kbe: Nice!
Some more detailed questions, maybe it is already included in your answer ‘everything worked well’, but just for double-check:
With ‘No’ you mean it was not restored or you didn’t try to do so?
I don’t know where to look about the homescreen-settings in TB…
is this included in the entry “Fairphone OS 1.1”?
Here I can see entries like “launcher.db”, “org.fairphone.launcher_preverences.xml” , …?
It is the only entry where I could find the string “launcher”…
So could this be the correct for homescreen icons?
@kbe says, he/she did the backup on 1.8, which has a new launcher (Version 2). 1.6 had the old launcher (Version 1), which is also included in 1.8.5.
So, @therob, if you do a backup on 1.6, the launcher icons should be restored in 1.8.5.
@Stefan: OK, thanks for this reminder.
But my particular question was, if all the userdata(Homscreens/icons) are included/connected in the backup of the TitaiumBackup entry “Fairphone OS 1.1” or if it is stored at another place?
Oh, I answered your other question… (“With ‘No’ you mean it was not restored or you didn’t try to do so?”) 
What you could try to verify, if the files store the icons, is to rename them and see, if the icons disappear.
I made a full backup. I didn’t explicitly tried to include or exclude the preferences for homescreen and icons. So I think the backup of Fairphone 1.8 settings are not compatible with the Fairphone 1.8.5 settings.
Sorry. I don’ t know that either. Can not answer that question.
By chance I found an old topic which is related to the backup question:
Today I have been brave enough to finally apply the UnifiedStorageUpgrade after verify my BackUps performed with TitaniumBackup (TB, Free version) and the build-in Back&Restore Tool of Android to an extern SD card.
UntilI now I am very happy with the progress since I could not figure out ANY problems while migrate my back-ups again to the system with TB.
I will report back later some more details but I could successfull restore:
I am very pleased about this and will report back later more details how I got it worked.
So now that I finally had to use Titanium Backup I’m going to share my experiences as well:
Pros:
(little) Cons:
But all in all: big thumbs up 
Sorry for not getting back to you, @therob. I took a break from the forum for nearly a month now. Just To answer some of your questions:
I could not figure out what I did wrong considering the contacts. AFAIR, the “etc.” concerned the wallpaper, ringtones, alarm soundfiles, and contact pictures. The latter had a strage side effect: I used to have high-res contact pics. (When tapping on a pic in the People app, you can see the original resolution.) Since the restore (the ‘second’, non-Titanium, via the ‘internal’ MediaTek B&R app) after updating to 1.6, all “old” contacts have low-res pics. New contacts have proper resolution, like before. And the backup/restore process when updating to 1.8.5 worked nearly flawelessly, BTW: everything was restored except the alarm soundfiles and ringtones. Which does not really matter.