Always look at the "System Update" info before installing. Also you mean MK3 right?
If you have your App Data Synced to Google then there should be no reason why it should not download and sync your data to your device....... Unless that is not the type of data it syncs, then your luck has run out. Also, do not restore a Nand backup from a previous version. It contains everything from the previous version bootloader to include the cache, data, recovery, and system info. Now all this was depending on what you picked to back up.
If you must or require extracting data or files from a previous Nandroid backup you made, you can use an app called Nandroid Manager ( just search for it here by member H3R3T1C or Google Play ). You can physically go into your backups and extract APK's, files, etc. Now where you have to go and look for your info, that is up to you to find it or find out where the game backups are stored.
Since you are now ND8, your are there and there is no going back. You can flash Custom Roms from previous as long as they do not include the older bootloader and as far as nandroids are concerned, you can restore a Nandroid that includes your current or the newest Bootloader with an older Rom saved with it ( that has been my understanding since day 1 -- correct me if I am wrong anyone....) .
I have yet to brick any of my phones doing it this way and they are all on the newest Bootloaders.
If you have your App Data Synced to Google then there should be no reason why it should not download and sync your data to your device....... Unless that is not the type of data it syncs, then your luck has run out. Also, do not restore a Nand backup from a previous version. It contains everything from the previous version bootloader to include the cache, data, recovery, and system info. Now all this was depending on what you picked to back up.
If you must or require extracting data or files from a previous Nandroid backup you made, you can use an app called Nandroid Manager ( just search for it here by member H3R3T1C or Google Play ). You can physically go into your backups and extract APK's, files, etc. Now where you have to go and look for your info, that is up to you to find it or find out where the game backups are stored.
Since you are now ND8, your are there and there is no going back. You can flash Custom Roms from previous as long as they do not include the older bootloader and as far as nandroids are concerned, you can restore a Nandroid that includes your current or the newest Bootloader with an older Rom saved with it ( that has been my understanding since day 1 -- correct me if I am wrong anyone....) .
I have yet to brick any of my phones doing it this way and they are all on the newest Bootloaders.