NiNTENDO 3DS FiRMWARE 5.1.0-11. Just another bloody update.
What's new
Some users received an error during the system update and were then unable to access the System Settings, Nintendo eShop, or Game Notes. This update prevents this from occurring again.
All cards that are compatible with the 5.0.0-11 firmware will work on this firmware. Sorry about the lateness of this update, I didn't know!
It's worth to note that this update brings a good few behind-the-scenes patches which may or may not prevent you from using 3DS homebrew in the future or at least make it more difficult. It patches numerous vulnerabilities in NATIVE_FIRM. Update at your own peril and don't complain that you weren't warned.