Thanx Alpha. You are our electronics main man
Yup, the Eprom is where Windows plonks their boot-loader... The actual Mobo IRQ's are in a different location and specific to the CPU, RAM etc.. those need to be verified for booting.. I will be concerned if those were overwritten.. nevermind a huge security risk..
We are talking about UEFI system firmware binaries packaged like device drivers to be delivered to target systems through WU. Once delivered, a component of the Windows UEFI Firmware Update Platform installs the firmware on the system. The process requires a restart and upon successful update, if in doubt, the new version can be verified from inside the system's BIOS besides other means of verification. I don't think this applies to systems with legacy BIOS.
Here's an excerpt from the documentation linked above in one of my previous posts
"Windows supports a platform for delivering system and device firmware updates wrapped in driver packages that are delivered using Microsoft Windows Update (WU) and then handed off to and processed in the UEFIUpdateCapsule function. This platform provides a consistent, reliable firmware update experience, and it improves the ability to deliver important system firmware updates for end-users. This ability has been available as early as Windows 8.1"
As indicated in the above excerpt, the platform can also be used to deliver and install device firmware updates such as for the video BIOS.
Thanx Alpha. You are our electronics main man
Yup, the Eprom is where Windows plonks their boot-loader... The actual Mobo IRQ's are in a different location and specific to the CPU, RAM etc.. those need to be verified for booting.. I will be concerned if those were overwritten.. nevermind a huge security risk..IRQ's etc is as far as I know handled by the chip-set, Northbridge, Southbridge etc. Some are negotiated (for lack of a better term) on boot up. A BIOS flash can set everything back to factory defaults. An inconvenience but not the end of the world.
Take the above definition with a grain of salt I guess? On my Raspberry Pi, the Firmware is stored on the Micro SD Card. All thats on the Pi is a very basic level 1 boot loader. Its not flashable no way no how. You can't brick it by updating the Firmware < Thats what the Pi foundation calls it. Doing a Firmware update just writes new code to the Micro SD card. It is non volatile so I guess it still meets the definition? Easily rewritten though. Kind or off topic but related.
The Microsoft document in the link below describes the update process in detail
https://docs.microsoft.com/en-us/win...ing-the-update
The process diagram is self-explanatory
Simply put, you can liken the mechanism to that of a Trojan in that the system firmware update binary payload is packaged to seem like a device driver and is handled as such until it is delivered to the system and handed off to the platform firmware for updating. ;-)
Last edited by PrivacyFreak; 25 Dec 2018 at 10:56.
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