slightly altered chargen (VENDOR + G/M produces 1px bar) for Mega65 native mode

doc/Development.md

@@ -59,6 +59,12 @@ There is no official PETSCII code for `TAB` - we can't utilize the ones from C12
 
 Bits 3 and 4 are extension to the original variable, compatible with the C128 ROMs API. There is no official way to retrieve `NO_SCRL` status as of yet. The `40/80` key status cannot be retrieved in C64 mode at all (C128 hardware limitation).
 
+#### Mega65 native mode
+
+Mega65 build starts in legacy mode, which is intended to be reasonably compatible with the C64 ROMs. However, a native Mega65 mode is planned too, to make it easier to utilise extra features of this machine. Soo far the following has been done:
+
+- Slightly different chargen. On C64 machines prewssing C= + G or C= + M key combinations produces the same visual result as C= + H or C= + N, respectively - despite keycap printing suggests they should produce tinner bars. This was intentional change in the C64 ROMs (compared to VIC-20), to prevent colour problems on 80s era TVs. Screen font used in the legacy mode duplicates this change, but the font intended for native mode has this change reverted back.
+
 
 ## Tinkering with OpenROMs