The header will be at
0x7xxx (for LoROM) or
0xFxxx (for HiROM) for the downloaded content. There may be more than one in a single Memory Pack.
xFB0-xFB1 = Licensee / Maker Code xFB2-xFB5 = Program Type xFB6-xFBF = Reserved xFC0-xFCF = Title xFD0-xFD3 = Block Allocation Flags xFD4-xFD5 = Limited Starts xFD6 = Date - Month xFD7 = Date - Day xFD8 = ROM Speed (unconfirmed) & Map Mode xFD9 = File/Execution Type xFDA = Fixed (0x33) / Licensee / Maker xFDB = Version Number (unconfirmed) xFDC-xFDD = Inverse Checksum xFDE-xFDF = Checksum xFE0-xFFF = Exception Vectors (Identical to SNES ROM header)
Titles may be rendered in Shift-JIS Japanese rather than using English text.
Licensee will be
0xFF. Reference to
$ffb0. Grab 2 bytes’ ASCII values for real licensee code.
Version Number is an extension. Actual format is
1 + ord(val($ffdb))/10. (Unconfirmed)
Inverse Checksum and Checksum must add up to
FLASH Download Requirements
For FLASH downloads, the data needs to be setup:
xFD0-xFD3 (Block Allocation Flags) must be set to 0xFFFFFFFF xFD6 (Date - Month) must be set to 0xFF xFD7 (Date - Day) must be set to 0xFF xFDA (Fixed - 0x33) must be set to 0xFF (though BS-X will overwrite 0x33)
BS-X will overwrite the values appropriately depending on size, on where it is downloaded, and when the file was available.
This explains the type of program that is contained. The value is 32-bit Little Endian.
0x00000000 = 65C816 Code & Generic Program 0x00000100 = BS-X Bytecode Program 0x00000200 = SA-1 Program Code (used for Itoi Shigesato no Bass Tsuri No.1)
BS-X treats every program type (other than BS-X Bytecode Content) as 65C816 Code & Generic Programs. The incompatible program contains code that will set up checks and display a message on screen before going back to the menu. Note that SA-1 Program Code does not apply for SD Gundam G-NEXT because there is no SA-1 code.
Block Allocation Flags
The value can be regarded as an allocation map (up to 32Mbit), i.e. where the data is actually stored on the Data Pack. One bit corresponds to one megabit block on the Memory Pack, with the MSB (bit7) being the last "page" (
$CE0000-$CFFFFF) and the LSB (bit0) being the first (
E.g. a 4MBit game with
$F0 originally resided in the upper half of the Data Pack and should be loaded there for emulation. Otherwise an error 09 will occur because checksum calculation fails: BIOS checksums
$C80000-$CFFFFF according to the map, but the game is stored in
The flags supports up to 32Mbit but there are only 8Mbit Memory Packs that have been officially released, but it is fully supported in BS-X.
If bit15 set: limited starts. number of starts left is determined by bits 0-14.
Boot Limits When a Satellaview download is booted from BS-X, BS-X will re-write xFD4-xFD5 if it's value is not 0x00. This is for the Boot Limit, designed to prevent bootup of downloads after a certain playcount. These are the known limited boot header values:
0xFC (11111100): 5 boots 0xBC (10111100): 4 boots 0x9C (10011100): 3 boots 0x8C (10001100): 2 boots 0x84 (10000100): 1 boot 0x80 (10000000): 0 boots (Game will not detect on BS-X) 0x00 (00000000): Unlimited Boots
The Date format goes like this (in bits):
%XXXX0000: Month %XXXXX000: Day
The data itself is copied from the downloaded BS-X Satellite File Directory's dates.
ROM Speed & Map Mode
ROM Speed (Upper 4 bits) 0x0 - 0x2 = SlowROM (200ns) X > 0x2 = FastROM (120ns) HiROM/LoROM (Lower 4 bits) 0 = LoROM 1 = HiROM
Sound Link settings and execution type
0x0? Bit0-3 (0000xxxx) = Unknown/unused (always 0) 0x10 Bit4 (000x0000) = Mute Soundlink Radio (1 = Mute, 0 = Unmute) 0x20 Bit5-6 (0xx00000) = Execution Area: 0 = FLASH (Used for games for that are more than 4M in size) 1 = Copy FLASH to PSRAM (Used for games that are less or equal to 4M) 2/3 = Fail 0x80 Bit7 (x0000000) = Skip the "J033-BS-TDM1 St.GIGA" Intro (0 = normal, 1 = skip)
The checksum is calculated by adding all bytes together, assuming 0x7FB0-0x7FDF (or 0xFFB0-0xFFDF in a case of HiROM game) are filled with 00h. When calculating the checksum, the Block Allocation flags are used to determine which blocks the checksum will be calculated from.
Conditions under which BS-X will not read/detect software data
These are all the known conditions under which the BS-X will not detect data (Not to be confused with conditions under which the BS-X will spew out an error when trying to play data.)
xFD4-xFD5's value is 0x80. Checksum and Inverse Checksum are blank. "Maker" value is not 0x33.