fixes to LOAD, some documentation updates

bin/README.txt

@@ -4,7 +4,12 @@ Follow these rules, or bad things will happen!
 
 - Don't mix ROMs for different platforms - use generic BASIC with generic KERNAL, Mega65 BASIC with Mega65 KERNAL, etc.
 
-- Don't mix these ROMs with any other ROMs; the only exception is CHARGEN, this one is fully interchangeable.
+- Don't mix these ROMs with any other ROMs; exceptions:
+
+   - kernal_hybrid.rom, which is meant to be used (and has to be used) with the original BASIC ROM;
+     however, this hybrid ROM cannot be distributed due to legal/copyright reasons
+
+   - chargen.rom - this one is fully interchangeable
 
 - Don't mix ROMs from different builds/versions (again, CHARGEN is an exception).