I promise tell my experiences as new user with Nokia N810.
I hope this thread helps people that has bought N810 after 2017.
Feel free to comment and ask and answer questions.

That stand is more useful when you keep hand. You can keep N810 very steady with 3 fingers with that stand. Menu button is also very useful with full screen button.

New miniSD card is hard to find and luckily my N810 comes with microSD to miniSD card adapter so I have to test my Sandisk Ultra microSDXC UHS-1 card 64 GB And it is amazing: N810 formatted it nicely and shows 59 GB free and works.

But where to get more room for applications to internal eMMC?. Control Panel / Memory/Device shows that there is only 30 MB free for applications and 1.8 GB for data. I had similar problem with N900: 2 GB for applications and 30 GB for data,

I had this solution with N900:
- I install Backupmenu and started with it to USB mass storage mode without starting OS. (If OS started normally, you can't repartition internal eMMC)
- I put N900 to Linux PC and it shows N900 as USB disk.
- I resize partitions N900 internal eMMC with PC Linux Gparted program to 16 GB for applications and 16 GB data without losing anything (if you do this, remember backup, because there can be always risk to data loss).

But how to do that with N810?
- Is there ever made BackupMenu for N810?
- If yes, in what repository?
- If not, is there another possible way to start USB mass storage mode on N810 without start OS?