How extract data from emunand

[RomikB]

My emunand broke when safe updating from 7.0.1 to 8.1.0. (possible 2.9 beta bug)
The screen is black after nintendo logo.
How can I extract my saves from emunand (partition on sdcard) or repair the broken emunand?

 

[RomikB]

So, is any guide how to fix incorrectly safe updated emunand with 2.9?
Devs fix it so it must be knowwhat goeswrong and how it can be fixed.