Warning: this page hasn't been updated in a long time. Most modern motherboards include graphical tools for logo replacement, and usually have enough space in the image to not require any dangerous ROM removal.

Replacing your BIOS logo

Flashing the BIOS on your computer is risky even if you don't modify it - flashing the BIOS with a modified BIOS image is very dangerous and may well result in a non-working motherboard that is very difficult, or even impossible to repair. Follow these instructions entirely at your own risk.
If your BIOS currently doesn't display any logo, and doesn't have any setting in the Setup, it is possible that it can't display the logo. In this case, you may check your motherboard manufacturer's website, to see if a BIOS update which can display the boot-up logo is available.
This guide assumes that your BIOS file is called BIOS.BIN.
These instructions were tested on GigaByte 7VAXP and VIA Epia Eden 5000 motherboards. They should work with most motherboards which use Award BIOS though. (If you don't know if you have Award BIOS, here's a screenshot of mine.)
  1. Requirements:
  2. Ensure that you have CBROM.EXE and TIFF2AWBM.EXE (from AWBMTools) somewhere in your PATH (if you don't know what this means, it's best that you don't play with your BIOS).The easiest way of ensuring this is to put all the EXEs in the same folder as your BIOS file
  3. Open a command console (MS-DOS box) and change to the folder where you have your BIOS. First check that your CBROM is compatible with your BIOS file. Type CBROM BIOS.BIN /D. You should get something similar to this: 
    E:\BIOS\GigaByte>CBROM BIOS.BIN /D
CBROM V2.01A (C)Award Software 1999 All Rights Reserved.

              ********     BIOS.BIN BIOS component ********

 No. Item-Name         Original-Size   Compressed-Size Original-File-Name
================================================================================
  0. System BIOS       20000h(128.00K) 13C67h(79.10K)  F13.BIN
  1. XGROUP CODE       0AEE0h(43.72K)  07B7Ch(30.87K)  awardext.rom
  2. ACPI table        042CFh(16.70K)  0170Eh(5.76K)   ACPITBL.BIN
  3. EPA pattern       0168Ch(5.64K)   0030Dh(0.76K)   AwardBmp.bmp
  4. YGROUP ROM        05EA0h(23.66K)  03F04h(15.75K)  awardeyt.rom
  5. Other(4029:0000)  05AE0h(22.72K)  02504h(9.25K)   _EN_CODE.BIN
  6. PCI driver[A]     10000h(64.00K)  09DEDh(39.48K)  RAID133.ROM
  7. PCI driver[B]     04000h(16.00K)  02524h(9.29K)   ATA133.ROM
  8. LOGO1 ROM         00B64h(2.85K)   0057Ch(1.37K)   dbios.bmp
  9. OEM0 CODE         02449h(9.07K)   01A70h(6.61K)   dbf.bin

  Total compress code space  = 36000h(216.00K)
  Total compressed code size = 31903h(198.25K)
  Remain compress code space = 046FDh(17.75K)

                      ** Micro Code Information **
Update ID  CPUID  |  Update ID  CPUID  |  Update ID  CPUID  |  Update ID  CPUID
------------------+--------------------+--------------------+-------------------

E:\BIOS\GigaByte>
    CBROM lists the files in your BIOS and gives some other information. Most important line is Remain compress code space = 046FDh(17.75K), which tells you that there's about 17 kB free space in your BIOS, space that can be used by the logo.
    Other interesting items are EPA pattern, which is the Energy Star logo displayed during boot-up and LOGO1 ROM, which is another image displayed during boot-up (in this case it's GigaByte's DoubleBIOS logo). EPA pattern and the logo can be safely removed from the BIOS to make more space for the full-screen logo.
    If your BIOS already contains a logo, a line similar to thisone will appear somewhere: 
      9. LOGO BitMap       4B30Ch(300.76K) 02ECBh(11.70K)  VPSD.BMP
    Note the uncompressed size, 300.76kB, this tells you that it's a full-screen logo. You will want to remove this.

    On the other hand, if your output looks similar to this, the CBROM version is not compatible with your BIOS: 
    E:\BIOS\GigaByte>CBROM.EXE BIOS.BIN /D
CBROM V1.30 (C)Award Software 1999 All Rights Reserved.

              ********     BIOS.BIN BIOS component ********

 No. Item-Name         Original-Size   Compressed-Size Original-File-Name
================================================================================
  0. System BIOS       937DC88h(151031.10000h(64.00K)  ô6} =»o2»X¼ÔßRó27-|Le_?  
          
  1. Other(5000:0000)  20000h(128.00K) 13C66h(79.10K)  F13.BIN
  2. Other(7F00:0000)  AEE000h(11192.007B5493h(7893.14Kô

  Total compress code space  = 30000h(192.00K)
  Total compressed code size = 7D90F9h(8036.24K)
  Remain compress code space = FF866F07h(-7780.24K)

E:\BIOS\GigaByte>
  4. If you wish to remove the existing full-screen logo from your BIOS, use the following command: CBROM BIOS.BIN /LOGO Release. To remove the EPA logo, use CBROM BIOS.BIN /EPA Release. For any other logos that may be in your BIOS, use CBROM BIOS.BIN /LOGOx Release. Replace x with the number that appears in the listing.
    You can also remove other parts of BIOS this way, however you will disable those hardware components by doing it. Eg. I removed RAID133.ROM from my BIOS, because I don't use the Promise controller as RAID. (There is still ATA133.ROM in there, which allows me to use it as normal IDE controller). If you have an on-board network card, there's a chance that boot ROM is included in your BIOS. If you don't boot off network, you can remove that ROM (it is only needed for booting, the network card will work fine without it). Remember though, that any of these actions can corrupt the BIOS and later render the system unbootable. If you wish to remove other parts of BIOS, run CBROM without any parameters, it will tell you which switches you can use.
  5. If your logo is already in AWBMP format, you can skip to step 6. Otherwise, here are instructions on how to prepare the logo:
    1. The logo dimensions must be 640x480 pixels with 256 colors. However, you should avoid using too many colors at once, and the image shouldn't be dithered to improve compression. You might find it necessary to reduce the number of colors to be able to squeeze the image into your BIOS.
    2. Save your image as a TIFF (Tagged Image File Format) file.
    3. Use TIFF2AWBM.EXE to convert the image to Award Bitmap format: TIFF2AWBM myimage.tif myimage.bmp. Note that output file name must not be longer than 8.3 characters. Also, Award BMP format is not compatible with Windows BMP format, even though they use the same extension.
  6. To insert your logo to the BIOS, run CBROM BIOS.BIN /LOGO myimage.bmp. If it succeeds, you'll see something like this: 
    E:\BIOS\GigaByte>CBROM.EXE BIOS.BIN /logo new.bmp
CBROM V2.01A (C)Award Software 1999 All Rights Reserved.
Adding new.bmp ..................................... 19.4%

E:\BIOS\GigaByte>
    In this case, you can flash your BIOS with the newly prepared file. Remember that you do it at your own risk, so don't blame me if the system doesn't boot after flashing.
    Follow the instructions of your motherboard's manufacturer on how to flash the BIOS.

    If however, the image is too big to fit in the BIOS, you will get this message. 
    E:\BIOS\GigaByte>CBROM.EXE BIOS.BIN /logo new.bmp
CBROM V2.01A (C)Award Software 1999 All Rights Reserved.
Adding new.bmp ..................................... 19.6%
BIOS.BIN have not enough space for adding ROM. (Over A545h bytes)

E:\BIOS\GigaByte>
    The message also tells you how much more space is needed to store the image, however it's in hex. Use your fauvorite calculator to convert it to decimal (in the example, the compressed image is 42309 bytes too large).
    You can either try to reduce image complexity, or if you're more adventurous, you can try removing some of the ROMs in BIOS.