This page lists some major differences between each BIOS. A large chart displaying the differences between each BIOS can be found here. A similar chart for each debug BIOS can be found here.
You can check the MD5 hash of any BIOS against this list of hashes.
Cerbios
Latest version: 3.1.0
Pros:
- Hybrid Bios Retail / Debug for all Xbox revisions 1.0 - 1.6b
- 256KB size (fits all TSOPs and modchips)
- Support for all retail video modes on all Xbox revisions 1.0 - 1.6b (RF, Standard AV [Composite], Advanced AV [S-Video], Advanced SCART [SCART/RGB], HD AV [Component YPbPr])
- Experimental support for VGA mode on 1.0 to 1.4 consoles using mode pins 1+3 or 2+3, requires screen that supports Sync-on-Green or external sync separator (can be set in .ini)
- Experimental support for XboxHD+ running firmware v2.2.2, ElpisHD tool or PrometheOS required to change features
- Support for force 480i to 480p video mode. (can be set in .ini or CerbiosTool Config App)
- Fixed 1.6 480p video support, XBE patching for 480p video mode on 1.6 consoles is no longer required
- Support for AV cable check disable (can be set in the .ini or CerbiosTool Config App)
- Support HDD sizes up to 16TB
- Single & Multiple Extended Partition Support & Cluster Sizes
- Native XISO Support
- CCI (Cerbios Compressed ISO) support
- Boots All Originals / Unsigned Code / Backups
- Boots Debug XBE's
- Easy configuration via .ini file. Can also be edited or created with CerbiosTool Config App
- Support for UDMA 2 up to UDMA 6 (can be set in the .ini or CerbiosTool Config App)
- Modern No DVD mode (Complete Removal Of DVD Code, can be set in the .ini or CerbiosTool Config App)
- Customizable boot animation. Possible to use an XMV video file as a boot video
- 128MB RAM support
- Custom Error Messages With Full Explanation
- Universal Region Fix
- Support for Force-PAL, an automatic setting that switches console region to PAL video mode for certian PAL-only games
- Invalid time reset
- Support for optional RTC module
- Macrovision Protection Disabled
- Dual HDD Support
- Safemode, Press Eject to force UDMA2 on boot
- Automatic reboot into safe mode (UDMA2) if error 9 or 13 is occurring
- Parental Control Removal
- No Reset On Eject
- Support for IGPC/In Game Power Cycle, IGS/In Game Shutdown, IGR/In Game Reset (button mappings can be set in CerbiosTool Config App).
- Ability To Launch Cerbios as a BFM Bios via PBL Methods
- Ability to block Xbox Dashboard Updates for BFM/softmod use (can be set in the .ini)
- Fixed 1.6 fan speed issues
- Detection of CPU upgraded console for increased fan speed to 60%
- Does not block Xbox Live or Xbox Live replacement services (Insignia)
- Debugging support with XBDM
EvoX M8+ / EvoX M8+ 1.6
Pros:
- Boots fast
- 256KB size (fits all TSOPs and modchips)
- In Game Reset (IGR) button combination
- Customizable boot animation colors
- Works with 1.6/1.6b Xboxes
Cons:
- Reconfiguring requires editing the .bin file with EVTool and then reflashing
- Does not support 128MB RAM (Titan patch can be used)
- Does not support LBA48 by default. Must be reconfigured with EVTool, or use a pre-patched version.
- Does not have DVD drive check disabled by default. Must be reconfigured with EVTool, or use a pre-patched version.
iND-BiOS 5003 / iND-BiOS Beta Feb-11-05 (5004)
Pros:
- Easy configuration via .cfg file. Can also be edited or created with iND-BiOS Config App
- 256KB size (fits all TSOPs and modchips)
- Multiple controller buttons combinations (Open/Close tray, Reboot/Shutdown console)
- Customizable boot animation colors and camera angles
- 128MB RAM support
- Debugging support with XBDM
Cons:
- IND 5004.06 will brick your modchip or TSOP, IND 5004.67 is fine
- Does not work with 1.6/1.6b Xboxes
- Injecting .cfg files directly into the .bin file on IND 5004 will brick the TSOP or modchip
- Slower booting with "loading ind-bios" appearing on-screen for several seconds as it checks the HDD for the .cfg file
- Using IGR while running certain games can cause the Xbox to crash (5004 only)
- Using IGR while running CoinOps can cause the Xbox to shutdown due to a conflicting button command within CoinOps (5003 only, a patched version that fixes this can be used)
- Blocks Xbox Live (a patched version that unblocks it can be used)
Xecuter 3 3294
More details and installation guides can be found on this page
Pros:
- Suite of options and tools in X3 Config Live
- Built-in Webserver/FTP
- Flash BIOS via FTP/HTTP
- Screenshot support (White+Black)
- Full LCD support
- Can disable mod via software
- Live customizable boot animation colors and angles
- 128MB RAM support
Cons:
- Need X3 chip or hacked version that will run on other chips (which also disables Config Live)
- 1024KB (1MB) size (only fits 1.0/1.1 TSOPs and some modchips)
Xecuter 2 5035 / Xecuter 2 5035 1.6
Pros:
- Easy configuration via .ini file. Can also be edited or created with X2 Config Maker
- Customizable boot animation colors
- 128MB RAM support
Cons:
- 512KB size (only fits 1.0/1.1 TSOPs and some modchips)
- "Xecuter2 Config Live Loading" text on screen for a few seconds as it checks the HDD for the config file
Xecuter 2 4981
Pros:
- Boots fast.
- 256KB size (fits all TSOPs and modchips)
- Can change boot colors and flubber animation
- 128MB RAM support
Cons:
- Reconfiguration requires editing the .bin file with XBtool and then reflashing
- Does not work with 1.6/1.6b Xboxes
Yoshihiro's Debug BIOS
Pros:
- High quality remote image capture (video and screenshots)
- Can poke live memory while playing games
- Can test homebrew you've made more thoroughly
- 256KB version available; support for F and G drives
- Debugging support with XBDM
Cons:
- No advantages of other custom BIOSes, it's essentially stock with the above features
Cromwell
Pros:
- Open source; sometimes included on modchips
- Can boot Linux
- Can lock/unlock HDD and install another BIOS
- 128MB RAM support
Cons:
- Can't run Xbox games
XBlast OS
Pros:
- Open source
- Can run scripts, boot Linux, and boot individual memory banks of modchips
- Can lock/unlock HDD, install another BIOS, edit MAC address, and modify the EEPROM
- Can fix a corrupted EEPROM or TSOP
- Can test RAM banks individually (useful for 128MB RAM upgrade)
- 128MB RAM support
Cons:
- Can't run Xbox games.
XeniumOS
See this page for a complete detailing of this BIOS.
Pros:
- Used as a recovery menu in which you can configure virtual BIOS banks for modchips with different BIOSes
- Can edit hard drive configuration
- Can change EEPROM settings
Cons:
- Used just as a tool; cannot run Xbox games or applications directly.
PrometheOS
See this page for a complete detailing of this BIOS.
.06 and .67 BIOSes
Amongst older BIOS releases (eg X2, EvoX, iND), there are commonly found variants with a .06 or .67 suffix to their names. These tags indicate the way that particular BIOS will handle extended partitions.
Microsoft's official BIOS releases for the original Xbox use LBA28 to map drives, limiting the total amount of storage that can be addressed to 128GB (237 bytes, or approximately ~137 billion bytes). This was more than sufficient for the drives they shipped with (which only offered ~8-10GB of storage), but modders upgrading those disks quickly ran into that barrier and found that their consoles were unable to allocate all of the space offered by their larger replacements. After the ~7.5GB required for the standard file system partitions E, C, X, Y, and Z (partitions 1-5), only around 120.5GB (~129 billion bytes) could be assigned to extended volume F (partition 6).
Another limitation of Microsoft's original BIOSes is that they cannot dynamically read partition tables from hard drives. Instead, they're hardcoded to expect each volume to be found at a static location on the disk: there's no flexibility in volume sizing.
In August 2003 oz_paulb released the first Xbox "LBA48 patch", which could be applied to a BIOS to improve its large drive support. More of a LBA32 patch: the new limit "only" reached 2TB (241 bytes, or approximately ~2.2 trillion bytes), although this was still far in excess of the disks available for purchase at the time.
Because some modders had already installed larger drives exceeding the older limit, BIOSes could be patched in one of two different ways: you could either opt for a BIOS which assigned all of the extra space to extended partition 6 (F) using a .06 patch, or you could spread it across extended partitions 6 and 7 (F and G) using a .67 patch. The .67 patch set the location of G at the 128GB mark on the drive, meaning that those who had already created a ~120.5GB F didn't need to reformat it in order to claim the rest of the space that had been made newly available. They could simply assign it to the next extended volume, G, instead.
Over time the "LBA48 patch" was upgraded, and support for on-disk partition tables was added. This meant that volumes of arbitrary sizes could be defined - for example, F and G could be sized at around 1TB each. That particular layout become very common place, as it turned out that additional cluster-related limitations prevented the use of singular volumes exceeding one terabyte in size: only 224 clusters can be assigned per volume, and only 64KB of storage could be allocated to each individual cluster. In any case, the use of on-disk partition tables meant that it no longer mattered whether you used a .06 or .67 patch, since you could largely just size your extended volumes in whatever manner you desired.
On-disk partition table support for up to 2TB of storage is available through NKpatcher-based softmods, such as those configured by Rocky5's installer. Because softmods only activate after the stock BIOS has initialised, they still require the standard partitions 1-5 to be sized in the manner that the stock BIOS expects. The extended partitions which follow, 6 and on-wards, can be custom sized.
When booting directly through a custom BIOS with on-disk partition table support (via some form of hardmod), all volumes can be custom sized: although it's still recommended to leave the standard partitions at their standard sizes for maximum compatibility with games. On-disk partition table support for up to 2TB of storage can be found in the following flashable BIOS types (and probably some others):
- CerBIOS
- X2 5035
- iND 5003
- EvoX M8+ (only if oz_paulb's patches are applied through EVtool)
It's notably not available in the X2 4xxx range.
Team CerBIOS released CerBIOS in Februrary 2022, initially with an 8TB limit (243 bytes, or approximately ~8.8 trillion bytes). In that same month, gaasedelen released the Titan patch with a 16TB limit (244 bytes, or approximately ~17.6 trillion bytes). These releases also offered improved UDMA modes, allowing for faster transfer speeds.
At some point CerBIOS may've also been updated to handle 16TB drives? Maybe? Probably? There's nothing in the change logs about it, and the BIOS seems to lacks an official "current list of features" doc, but this generally seems to be accepted as fact.