If by "rom call" you mean a bios call, then yes its legal as long as you don't
do anything stupid and distribute any copyright material such as the bios with
your work.
In message <F186eOLn9WdjpdsKkSX0000c569@...> gbadev@yahoogroups.com
writes:
> Hello, its legal use rom call to gba in my project?
>
> thanks