OS 2.41 ONLY, page 1Ch/3Ch/7Ch, address 6A6Fh. Writes up to 255 bytes to a specified Flash ROM data page and address. Inputs: (pagedCount): number of bytes to write. This is reset to zero within the routine. (arcInfo): Flash ROM page to write to. This must be between 8 and 15h/29h/69h inclusive. (iMathPtr5): address to write to. (4000h-7FFFh) pagedBuf: bytes to write. Outputs: (iMathPtr5) and (arcInfo) updated with new values.