BattleTech: FireStorm — V5.1.0b_RC1

Release notes for pod owners · 25 July 2026

This build covers everything since the -tbaud RIO update. It is a large release: 58 changes spanning multiplayer, cockpit hardware, displays, 'Mech content, the console lobby and the match printer.

The most important thing to know: if you change nothing in your configuration, this build behaves like your current one. Every new feature listed here is either a fix that applies automatically, or an option you have to switch on deliberately. Nothing new is enabled by default.

1. Read this first -- required on Windows 10 / 11

Run `set-appcompat.bat` after installing

A new one-click tool ships in your install folder. Double-click set-appcompat.bat once, after copying the game to its final location.

FireStorm renders in 16-bit colour, and modern graphics cards no longer offer 16-bit display modes. Windows can emulate them, but only if the game is registered for it -- and that registration is tied to the exact folder the game sits in. Copying or moving an install silently loses it.

Without it, the game fails to go fullscreen and reports:

"Another application is preventing use of full screen mode."

That message is misleading. It is not another application. It is this registration missing. If you see it, run set-appcompat.bat and restart the game.

Run it again any time you move, copy or reinstall the game to a different folder.
Right-click -> Run as administrator to apply it for every Windows account on the pod.
It reports what it changed and takes effect on the next game launch. No reboot needed.

2. Multiplayer

16 pilots plus a cameraship now launch correctly

Previously, a full 16-pilot game with a cameraship connected would silently fail to launch ? you pressed launch and nothing happened, with no error. Fixed. A cameraship no longer consumes one of the 16 pilot slots.

No configuration needed. This applies automatically.

Load File -- set up a whole match from a file

The console lobby can now load an entire match configuration -- game type, map, mission options and all 16 player slots -- from a single file, instead of setting everything by hand.

To enable it, edit options.ini in your game folder -- the same folder that contains MW4.exe, for example C:\MW4\options.ini -- and add:

[automaticmode]
automaticmode=1
automaticfile=matchsetup.ini

Both keys are required:

Key	What it does
`automaticmode`	`1` shows the Load File button in the console lobby. Any other value, or the key missing entirely, hides the button and the lobby behaves exactly as before.
`automaticfile`	The match configuration file the button loads. If this key is missing, or points at a file that does not exist, the button appears but does nothing when pressed.

automaticfile can be either a plain file name, which is read from the game folder next to MW4.exe (so automaticfile=matchsetup.ini reads C:\MW4\matchsetup.ini), or a full path if you prefer to keep your match files somewhere else (automaticfile=C:\PodConfigs\friday-night.ini).

Full file format reference: BTFrstrm/autoconfig-file-spec.html
Two ready-made examples -- copy one into your game folder and point automaticfile at it: BTFrstrm/test-ffa-coliseum.ini and BTFrstrm/test-team-koth-centralpark.ini

Read BTFrstrm/autoconfig-file-spec.html before writing your own match files. Open it in any web browser. It documents every section and key, the accepted values for each, what happens when a key or section is left out, and complete worked examples for both free-for-all and team matches. It is the authoritative reference for the file format -- this page only covers turning the feature on.

The Default button restores standard settings, so you can always get back to a clean lobby.

Longer match times

The multiplayer time limit list has been expanded from 9 options to 18: 1 through 15 minutes, plus 20, 25 and 30. The dropdown scrolls to fit them.

3. Cockpit and RIO hardware

Throttle zero fix

The throttle now reports a true zero position and clamps negative values correctly. Previously the zero point could be skipped.

Applies automatically.

`-tbaud` -- support for high-speed replica RIO boards

If you are running a replica RIO cockpit board with a faster UART, you can now set the COM1 speed without changing anything else about how the board talks to the game:

MW4.exe -tbaud 115200

Accepts 9600 to 921600. Leave it off and the game uses the original speed, exactly as before ? existing original RIO boards need no change and should not use this switch.

This is only the speed. The wire protocol is untouched. (The separate -trio 1 switch changes the whole protocol and is not what you want for a replica board.)

4. Displays and MFDs

Split MFD mode -- two separate 640x480 MFD monitors

New display mode -tmfds 4, for pods using two separate 640x480 monitors for the MFDs instead of one wide spanned display.

MW4.exe -tmfds 4

Four displays total: main, radar, left MFD, right MFD. The original spanned modes (-tmfds 1 and 3) are unchanged and remain the default for existing pods.

Split MFD stutter -- fixed

Early split-MFD builds had a constant rhythmic stutter across the whole game. Fixed. The two MFD panels no longer force the graphics card to stall every frame cycle.

Required dgVoodoo2 setting for ALL MFD modes on Windows 10/11

On Windows 10 and 11, dgVoodoo2 is required for every MFD mode -- including the original spanned display (-tmfds 1 and -tmfds 3), not only the new split mode (-tmfds 4).

If your pod drives any MFD or radar panel at all, this applies to you. It is not specific to the new split-MFD feature: the underlying Windows limitation affects every mode that lights up a second display. On Windows XP none of this was needed.

dgVoodoo2 is not part of the build, and must NOT be installed on Windows XP pods. XP uses the graphics support built into Windows and needs nothing extra -- adding dgVoodoo2 there will break it. It is a per-machine prerequisite that you install yourself, on Windows 10 and 11 pods only. If your fleet is mixed, set it up per machine, not as part of the game folder you copy around.

In the dgVoodoo2 control panel, on the General tab, set:

Scaling mode: Stretched, Keep Aspect Ratio

This is not optional and not cosmetic.

With Stretched (plain), the MFD monitors silently stay on the Windows desktop while the main and radar screens go black. There is no error message of any kind. It simply does not work.
With Stretched, Keep Aspect Ratio, all panels come up correctly.

The same setting also gives the correct picture geometry on 16:9 monitors. FireStorm renders in 4:3, so on a widescreen display it is either stretched out of shape or shown correctly with black bars down the sides. Keep-aspect gives you the correct shape -- circles stay round and the targeting reticle is accurate.

Why dgVoodoo2 is still required: we tested running the multi-monitor MFD modes on Windows 10 with no dgVoodoo2 at all, using every available configuration. Modern Windows only permits one display at a time to take exclusive fullscreen control, so the extra MFD panels are refused. Windows XP allowed it; Windows 10 does not. dgVoodoo2 works around this. There is no setting or switch that avoids it.

`-tmon` -- fix monitors coming up in the wrong order

If your panels appear on the wrong physical monitors, you can assign them explicitly, in the order main, radar, MFD 1, MFD 2:

MW4.exe -tmfds 4 -tmon 1,2,3,4

Use 0 in any position to leave that one on automatic -- -tmon 2,1,0,0 swaps only main and radar. Leave the switch off entirely and everything is detected automatically, which is correct on most pods.

5. 'Mechs and content

Six rookie 'Mechs instead of four

The console lobby's default rookie 'Mech rotation now includes the Archer and Warhammer alongside the original four. Right-click randomising picks from all six.

Corrected loadouts

Battlemaster (Inner Sphere) -- now carries its proper stock loadout: PPC, 6 medium lasers, 2 machine guns, and an SRM-6. It previously had only a single medium pulse laser.
Battlemaster 2C (Clan) -- ER PPC, 6 ER medium lasers, 2 Clan Gauss rifles, Clan Streak SRM-6.
Behemoth / Behemoth II -- Gauss rifles moved into the main weapon group so they fire with the rest of the primary weapons.

Restored missing artwork

Several 'Mechs were missing their MFD and cockpit display images, which showed as blank panels in game. Restored: Assassin II, Behemoth, Behemoth II, Black Hawk, Longbow, Solitaire, Victor, plus two missing lobby decals.

Mechlab label correction

The mechlab turn rate now reads "Turn Rate (Top Speed Rad/Sec)", which is what the number actually means. It previously claimed degrees per second, which was wrong.

6. Arcade / console mode

Configurable Rookie Mission

The quick-launch Rookie Mission was previously fixed in place. All of its settings can now be changed from the same options.ini in your game folder, next to MW4.exe.

This is the mission the console loads when it opens, and the one restored when Default is clicked in the lobby.

Every entry is optional. Omit the section entirely and you get exactly the previous built-in behaviour. The block below is ready to paste into options.ini as-is: every setting line is commented out with //, so pasting it changes nothing until you uncomment the lines you want.

[RookieMission]
// Default mission loaded when the console opens and when "Default" is clicked.
// All entries are optional - omit any to keep the hardcoded built-in default.
//
// MissionName   - exact display name as it appears in the map dropdown
//                 default: ScarabStronghold - Attrition
// GameType      - 0-based index into the game-type dropdown (2 = Attrition)
//                 default: 2
// TimeLimit     - time limit in minutes; -1 means use the server's default time
//                 default: -1 (uses g_nTimeList_Value, currently 7 min)
// Visibility    - 0=Clear 1=Light Fog 2=Medium Fog 3=Heavy Fog
// Weather       - 0=Off 1=Rain
// TimeOfDay     - 0=Day 1=Night
// Radar         - 0=Novice 1=Off 2=Bars 3=Unlimited
// HeatOn        - 0=Off 1=On
// FriendlyFire  - 0=Off 100=Full (percentage)
// SplashDamage  - 0=Off 1=On
// UnlimitedAmmo - 0=Off 1=On
// WeaponJam     - 0=Off 1=On
// AdvanceMode   - 0=Off 1=On
// ArmorMode     - 0=Off 1=On
//
// Example: uncomment and edit lines below to customize
//MissionName=ScarabStronghold - Attrition
//GameType=2
//TimeLimit=-1
//Visibility=0
//Weather=0
//TimeOfDay=0
//Radar=0
//HeatOn=0
//FriendlyFire=0
//SplashDamage=0
//UnlimitedAmmo=1
//WeaponJam=0
//AdvanceMode=0
//ArmorMode=0

Two worth knowing:

MissionName must match the mission's display name exactly as it appears in the map dropdown, including spacing and the - before the game type.
TimeLimit=-1 means "use whatever time limit the server is currently set to" rather than forcing a fixed value.

7. Match printer (mw4print) -- version 2.0

Custom banner text

The line printed at the bottom of each score sheet is no longer fixed to WWW.MECHJOCK.COM. Set your own via File -> Banner Setting.... It is saved to banner.txt next to the printer, so you can also edit it directly.

Database export (included, not yet field-tested)

mw4print 2.0 can export match results -- scores, kills, player-versus-player results -- to an external MySQL database after each print job, for league tables or long-term stats.

Configure via File -> Database Settings (Ctrl+D), or the [MySQLExport] section of mw4print.ini. The table layout is documented in db_schema.sql.

?? This feature has not yet been tested against a live database server. It is off unless you configure it, and printing works normally without it. If you try it, please report back.

8. Quality of life

`mw4.exe -help`

Running MW4.exe -help now opens a complete reference for every command line switch -- around 76 of them, grouped by category with descriptions. It opens in Notepad and the game does not start.

English error dialogs

The crash and error dialog buttons previously appeared as ??? boxes on some systems, because the shipped language file was a Korean build. They now read More Details / Continue / Exit.

Performance measuring -- `-fps`

For diagnosing stutter or verifying a pod is running smoothly:

MW4.exe -fps

Writes gos-fps.txt next to the game with a per-second breakdown -- average frame rate, the slowest frames, and a count of stutters -- plus a summary at the end. Off unless you ask for it, and it costs nothing when unused.

Display troubleshooting log

When display problems occur, the game now writes gos-displays.txt next to the exe listing every monitor it found, which role each was assigned, and the exact reason any panel failed to start. Previously such failures were completely silent. Include this file with any display fault report.

9. New command line switches at a glance

Switch	Purpose	If you leave it off
`-tmfds 4`	Two separate 640x480 MFD monitors	Existing MFD mode unchanged
`-tmon a,b,c,d`	Force monitor order: main, radar, MFD1, MFD2	Automatic detection
`-tbaud <rate>`	COM1 speed for replica RIO boards	Original board speed
`-fps`	Write a performance log	No log, no overhead
`-help`	Show the full switch reference and exit	Game starts normally
`-tcoop <0-5>`	Display troubleshooting only -- do not change	Standard behaviour (0)

10. Known issues and limitations

Every MFD mode requires dgVoodoo2 on Windows 10/11 -- the spanned modes (-tmfds 1 and -tmfds 3) just as much as the split mode (-tmfds 4) -- with scaling set to Stretched, Keep Aspect Ratio. This is a Windows limitation, not a bug we can fix.
The MySQL export in mw4print has not been tested against a live server.
The game renders in 4:3 only. There is no widescreen mode. On 16:9 monitors, use keep-aspect scaling for correct geometry with black bars at the sides.
The AppCompat registration is tied to the install folder. Move the game, re-run set-appcompat.bat.

11. Upgrade checklist

Back up your current install.
Copy in the new build.
Double-click set-appcompat.bat (as administrator if the pod has multiple accounts).
On Windows 10/11, confirm dgVoodoo2 is installed and its scaling mode is Stretched, Keep Aspect Ratio. This is required for every MFD mode -- spanned (-tmfds 1 / -tmfds 3) as well as split (-tmfds 4). Windows XP pods do not need it.
Launch and confirm the console lobby reads the new version.
Play one mission end to end before putting the pod back into service.
Optional: add [automaticmode] and [RookieMission] to options.ini if you want the new Load File button or custom rookie missions.