All,
Be careful when buying boards from FriendlyArm / FriendlyElec. If there are problems with the board it will not be fixed. And you will have wasted your money.
My R4S arrived and only booted a few times. I looked over the board expecting to find a solder blob or silver whisker. I did find an IC not properly seated (I can supply a picture).
I informed FriendlyArm / FriendlyElec of the problem within 24 hours and then I shipped the R4S back for replacement or repair. After 4½ months of waiting they decided the IC was my fault and that I damaged the board. No refund, and no replacement.
In my opinion we should not be recommending the FriendlyArm / FriendlyElec boards.