warning: main bios checksum error. - Page 1
Forum section: electronics / repair

author: lepden
author_rank: Contributor
timestamp: April 19, 2017, 02:20:31 am
content: I have a Gigabyte motherboard with me which gives the message "Warning: main bios checksum error" right after POST and then some dots will follower after the text and reboots. However, if I press ctrl+alt+del while showing the warning I can access the bios setup (does it mean this is not a bios problem?). I've searched through the internet and it seems a common problem in Gigabyte mobos. I've tried replacing CMOS battery, resetting bios, taking out ram, upgrading the bios, nothing works. Came across this:http://www.badcaps.net/forum/showthread.php?t=51505which looks promising. I wanna know if it will work if I solder a chip that fit the size and shape or does it have to match the numbers on the chip? What if I desolder both the bios chips and solder the b_bios chip on the m_bios connector, will it work on only one bios chip?

author: theatrus
author_rank: Frequent Contributor
timestamp: April 19, 2017, 03:26:03 am
content: Chips are not chips by shape and size - they need to form the same function.The article linked mentions what type of chip it is, specifically a SPI flash with a specific size and specification. Replacing it with the same model chip, which appears to be freely available from multiple distributors for less than a dollar, is essential in a repair unless you can determine a replacement is compatible.

author: lepden
author_rank: Contributor
timestamp: April 19, 2017, 03:58:38 am
content: Thanks for the clearing my doubt. What about my second question? Will the mobo work on single bios chip?

author: Jeroen3
author_rank: Super Contributor
timestamp: April 19, 2017, 05:35:57 am
content: You have a dual bios board I presume?This means then you are now running on the backup bios. It should work fine, but there is no further backup.Many boards don't have dual bios anyway.The fix you linked assumed a broken flash chip. When replaced, the contents of the backup are copied to main, and it will work again.Ifthat is the problem.

author: lepden
author_rank: Contributor
timestamp: April 19, 2017, 05:49:21 am
content: Yes, it is a dual bios motherboard. Assuming the main bios chip is corrupt, I'm wondering if it will work if I replace the m_bios chip with the b_bios chip. I'm in India and these chips are not easily available.Ok. I got you, it should work you meant.

author: wraper
author_rank: Unknown
timestamp: April 19, 2017, 06:31:11 am
content: First you should try forcing copying bios from backup to the main chip, if possible. By upgrading bios, you are not doing full programming, only partial. You can replace it with different chip, however it must be one of a few chips compatible with particular board. Otherwise it won't be possible to program it within mobo, only by programmator before soldering. And even then, firmware updates won't work. SPI FLASH ICs can be read the same way but programming is different.http://www.overclockers.com/forums/showthread.php/697533-GUIDE-Forcing-backup-BIOS-on-Gigabyte-motherboards

author: lepden
author_rank: Contributor
timestamp: April 19, 2017, 07:14:10 am
content: Thank you. I'll try that out.

author: lepden
author_rank: Contributor
timestamp: April 19, 2017, 01:59:36 pm
content: It's alive!!! I soldered the b_bios chip to the m_bios chip connector and and it's working. Now I don't have the advantage of dual bios but it's fine as long as it working. Thanks guys for all your help.

author: james_s
author_rank: Super Contributor
timestamp: April 19, 2017, 08:17:23 pm
content: You should get a replacement chip and flash it with the backup bios, something cheap like a TL866 will do this, likely you can find someone to burn a chip for you for a small donation. The backup BIOS chip *may* be a non-erasable EPROM rather than the flash used for the main BIOS. If that's the case then you'd need to switch it back. If it were my board I would consider installing a socket, I don't like soldered ROM chips.

author: lepden
author_rank: Contributor
timestamp: April 20, 2017, 01:25:05 am
content: Ok, so what am I risking here?