file_binary
File mode: Binary. Open file as binary rather than text. This mode must be combined with file_read and/or file_write. For example: file_binary + file_read, file_binary + file_write, or file_binary + file_read + file_write
const file_binary = 0x04
import fileio
f = file("data.bin", file_binary + file_read)
byte = f.readbyte(0)
f.close()