How did you try to update, via the LibreELEC addon or manually?
I know you said you chose the correct file but can you try it via the LibreELEC addon.
If you have a different skin installed revert back to the original before updating.
Using the LE addon will just make sure to download the right file.
Did you revert back to the original skin?
You can also try to delete the "addons27.db" file, but make a backup before.
Just did the upgrade from 7.0.3 to 8 on my RPi 2. The upgrade appeared to proceed fine, it rebooted and then froze on the LibreElec boot screen - Libreelec 8.0 official in top left of screen. Tried another twice and also tried beta 3 - same situation. I used the correct update file.I re-wrote the SD card with 7.0.3 and restored so back to where I was.
Any suggestions - I would like to update to 8.0?
I have exactly the same issue when updating from 7.0.3 to 8 on my RasPi 3. 
I tried 2 things, both end with the same result:
I hope someone has a solution. 
Well if this is where we're at, I'm sticking with 7.0.3 then. I left for work today knowing that 8.0.0 had been finally released. So the first thing I did when I got home was make an SD card image of my RPI3 running 7.0.1 (I haven't updated in a while). Then I booted up, went to the LibreELEC addon and did the update to 7.0.3. Then after rebooting again, I chose the 8.0.0 update channel, and then the 8.0.0 RPI2 build from the addon. Installed ok, rebooted, then stays at the LibreELEC boot screen, never loading Kodi. It would be nice if we could access a log to see what is actually locking the system up.
Has anybody tried installing one of the previous beta builds? Maybe something that was added to the 8.0.0 final broke RPI's.
add "debugging" to cmdline.txt and you will see on-screen output from journald that is normally hidden; it might give you a clue
i am having the same problem on my CuBox-i-4. Updated on SD card with first librelec USB SD writer and after tha twin32 disc imager, none of them booted.
Have now restored my original 7.95.3 and will try manual update.
EDIT:
Manual update by placing the files in update folder worked without problem.
All,
I've created a log at the frozen boot screen. Please find here: aPZa
It says something about a missing SQL database?
EDIT:
OK. I solved it for me.
- Installed 7.0.3 and restored the backup created in 7.0.3
- Updated manually by putting the 8.0.0 file in the .update folder
- Rebooted and got stuck at the Kodi logo as before
- Fired up SSH and deleted .kodi/userdata/Database/Addons27.db and rebooted by reboot command
- Got stuck again at “Add-on migration in progress – please wait”. Waited for 5 minutes and then rebooted again by reboot command
- Got an error message that one Add-On is incompatible. Uninstalled that.
Now everything works fine. I hope that this may help others. 
Does deleting the "Addons27.db" file cause you to lose your addons, or just the settings they have? Would this also include things like skin customizations, favorited links and remote control configs? I've heavily modified my setup with a skin using various "Super Favorites" to make home screen shortcuts. I've also had to customize the way my remote control works. I'd hate to lose all of this. The proposed fix is just a "bandaid" and not a "solution". The LibreELEC team needs to step in figure out what's really going on.
You won't lose your settings.
Create a backup, delete Addons27.db, update, if anything goes wrong just restore from backup.
BTW Addons27.db is Kodi related not LibreELEC.
Confirm. No settings or addons lost. I don't know exactly what that file is for. But Kodi worked fine after I deleted it.
I just did an SD card image restore back to 7.0.1. I then (out of curiosity) SFTP'd into my Pi to see that "Addons27.db" file. Believe it or not, MY file was 0 bytes in size. There was nothing there. So I'm not even sure what that file is used for, or what created it. I do know the "when" though, as it says it was created (or at least modified) on 2/5/17. I'm too tired to keep messing with this tonight, but I'm going to try erasing that file tomorrow, then use the LibreELEC addon's built in updater to see if it works afterwards. If not, I'll do what everybody else is reporting is working by SSH'ing in and erasing that file after performing up the update.
Strange though huh? A single file, with 0 bytes, causing a complete lockup of the boot sequence?
I just updated to V8 as well on two machines (manual update from the LibreELEC menu). The first one (Intel NUC) looped during migrating databases. After deleting the Addons27.db and power off/power on it finally booted, but the system says my libraries are empty (I am using a mySQL database for several machines). I see my sources and contents, but obviously there isn't any connect to the SQL DB any more.
The second upgrade fulfilled without any loop, but the same result. All libraries are empty. How can I re-connect to the SQL DB?
I just updated to V8 as well on two machines (manual update from the LibreELEC menu). The first one (Intel NUC) looped during migrating databases. After deleting the Addons27.db and power off/power on it finally booted, but the system says my libraries are empty (I am using a mySQL database for several machines). I see my sources and contents, but obviously there isn't any connect to the SQL DB any more.The second upgrade fulfilled without any loop, but the same result. All libraries are empty. How can I re-connect to the SQL DB?
For me the solution was "Wait for nerwork" (30 sec).
For me the solution was "Wait for nerwork" (30 sec).
I tried this without success - personal library is empty, i. e. there still is no connect to the DB. This way the V8 is useless for me and I will go back to 7.0.3.
