Hyosung uses different plugs for their reg recs, go on ebay and try these i am very sure one of them will charge fine. Cheap test parts , you get 3 anyways to tide you over for a long while.
https://www.ebay.co.uk/itm/256113919119
Shop has upgrade stators and upgrade regs with a lifetime warranty of the reg, think about that in the future
Now C12 code , yes there is a topic on this forum about “alternative starter motors” to use to crank the bike up.
Follow service manual with a meter when it asks
– how many ohms stator
– how many ohms spaking coils
– how many ohms injectors
The ECU will flag up if it doesn’t like the resistance going to them.
(more resistance in wires usually means , it will burn when she is hot , eventually, more like a slow kill)