Choosing An Emulator Build

Choosing an Emulator Build

The hacked backward compatibility pack ships six versions of the emulator and gives you almost no guidance on which to install. This page is that guidance.

Short answer: 64MB / Regular. Move up only when you want something specific.

The two choices, and they are independent

The six folders are every combination of two separate decisions:

64MB/  Regular   HUD   HUD_plugins
128MB/ Regular   HUD   HUD_plugins

First choice — how much memory the emulated Xbox has

64MB	What a retail original Xbox had. Fully tested and working, per the pack's own readme.
128MB	What an original Xbox development kit had. The pack calls it experimental and says "I have no idea if this actually works, please thoroughly test this".

The 128 MB builds carry a patched original Xbox kernel (xb1krnl, credited to Yoshihiro) that lifts the memory ceiling. Retail games were written for 64 MB and gain nothing from it — the reason to want 128 MB is homebrew or debug Xbox software that expects devkit memory.

Take 64MB unless you are specifically running something that needs more.

Second choice — what the emulator lets through from the Xbox 360

Regular	Behaves like the stock emulator. No guide button in-game, no chat. Fewest moving parts.
HUD	The Xbox 360 guide button works while an original Xbox game is running, plus in-game and cross-game voice chat.
HUD_plugins	Everything HUD does, and external resources are no longer unloaded — so Aurora and FSD overlay plugins keep working inside the emulator.

The pack's readme is candid about the trade-off: HUD_plugins can crash if an Aurora plugin uses too much memory, and it suggests falling back to HUD, or to the alternate xbox.xex_HUD front end that unloads external resources before starting the emulator and reloads them after.

So the ladder is: start at Regular, step up if you want the feature, step back down if it misbehaves.

Does the console model matter?

No — not for this choice. None of the six variants is tied to a motherboard revision. A Xenon and a Falcon behave identically here; confirmed on hardware with both, where every patch and every bug reproduced the same on each.

What does depend on your console is whether backward compatibility is possible at all:

• It needs an internal hard disk. The emulator lives on a partition that only exists on one, and it keeps its work area on another. A console running from a 4 GB internal flash and nothing else cannot do this, and no emulator build changes that.
• Everything else — which drive, what size, whether it authenticates — is what the rest of this wiki is about. An unsigned drive works, which is the whole point of this fork.

What the xefu files are, and why there are so many

Inside every variant you will find the same list:

xbox.xex                       the front end: picks a profile and launches it
xefu.xex, xefu1_1.xex, xefu2.xex, xefu3.xex, xefu5.xex, xefu6.xex, xefu7.xex, xefu7b.xex
xefutitle5.xex, xefutitle6.xex, xefutitle7.xex, xefutitle7b.xex
dash/xboxdash.xbe              the original Xbox dashboard
dash/xodash/xonlinedash.xbe
dash/fonts/xbox.xtf, "Xbox Book.xtf"

The numbered xefu files are emulator versions, not options. Microsoft shipped seven updates to the emulator over the years and kept the old ones, because a game certified against one version is not guaranteed to behave on another. xbox.xex reads the title id off the game, looks it up, and launches the version that title was approved for. The xefutitle files are per-title overrides that go with the matching version.

You do not choose among these. Install all of them, as the folder comes.

The lookup table is TDBX/Tdbx.db — 163 MB, magic TDBX, and encrypted (entropy 7.997 bits/byte, not one readable string in the first 4 MB). The supported-title list cannot be read out of it. The hacked emulator removes the whitelist check, so titles that were never approved will at least attempt to run.

index and TDBX are not part of the pack and must be left alone when installing it.

Which one is on your drive?

Compare Compatibility/xbox.xex against the pack:

fusefatx -b hd -p x1 /dev/sdX /mnt/point
md5sum /mnt/point/Compatibility/xbox.xex 64MB/Regular/Compatibility/xbox.xex

xbox.xex is the front end and differs between Regular, HUD and HUD_plugins, so it identifies the variant on its own. To tell 64MB from 128MB, compare any xefu*.xex as well.

What is actually installed here

The 1 TB Toshiba used to develop this runs 64MB / Regular, verified by checksum against the pack at install time. That is the configuration original Xbox games were confirmed working on from an unsigned drive.