Homebrew I need help, I can't access the eShop on 10.6

[Deleted User]

My friend accidentally updated my 3DS from 9.2J to 10.6J.
I have no problem with updating, but the problem is that I can't access the eShop or Miiverse.
Doing so gives me the error code of 022-5540 for Miiverse, and 022-2634 for eShop. How do I fix this?
I have a NAND backup of my system when it was 9.2J, will that help?

 

[Pikm]

I have a NAND backup of my system when it was 9.2J, will that help?

sysNAND or emuNAND? sysNAND, yes, but you need a hardmod for it to be of any use. emuNAND, rebuild it.

 

[Deleted User]

SysNAND, unfortunately.

I'm a little relieved that I could at least downgrade in some way, but is there really no way to fix the eShop?