The body of the FIT file contains all the rest of the information mentioned previously, microcode locations and BootGuard/ACM keys, hash and policy file locations. The first entry is always the FIT header, this contains the GUID, header and data (body) checksum, type and attribute value, file size and state value.

Sometimes there is two actual locations (dual microcode files in seperate volumes), the FIT table only contains info to point the BIOS to the first microcode locations.įIT table also sometimes includes locations to Intel BootGuard/ACM keys, hash and policy locations. This contains the CPU microcode locations first called by the BIOS.

Standard built in windows calculator (Set to “Programmer Mode” with “Hex” selected on left), or any other hex capable calculatorįIT Table is often (Maybe always?) at GUID - B52282EE-9B66-44B9-B1CF-7E5040F787C1

Hex editor of your choice, I use paid version of Hex Editor Neo they do have freeware version too, another good one many use is HxD Hex Editor If this is broken in your stock BIOS, that’s not how it’s supposed to be, this only means manufacturer was being lazy and didn’t notice or fix, or has poor BIOS coding skills Please fix this for yourself even if not modifying your BIOS otherwise This guide applies mainly to modern Intel boards that contain a FIT table, if you do not see one in your BIOS with UEFITool NE Alpha, or you have AMD board, this guide will not be very helpful for you due to microcode edit section is not in-depth.įIT table can be viewed here with UEFITool NE Alpha, example of invalid and valid FIT is show, if you are reading this guide please enlarge so will see how to immediately recognize the difference Mainly this guide will focus on correcting FIT table, since redoing microcodes via hex is tough to explain guide-wise and the above guide already does a better job than I can at explaining that aspect. So here is my method of doing both of these edits, hopefully it will help fill in some gaps the other guide may leave for some users. There is already a guide here on how to update microcodes using these very same methods, which includes a brief section on correcting FIT table, but some users have asked for a little more info/guidance on how to do both of these things especially FIT corrections… This is a quick requested guide I put together for someone, on how to edit CPU microcoded with UEFITool and how to update/correct the FIT table in some BIOS. Update CPU Microcode + Fix FIT Using UEFITool / Hex

Free instal UEFITool A68