Hello,
You can find here the source code for the chainload command (from Debian Unstable, in this case):Grub will check the two byte signature (usually 0xaa55) of the boot loader. Then, after this check, the computer will execute any arbitrary code loaded from the first sector of the chainloaded disk.
That's why it's a possible vector for the spread of computer viruses if the content of the disk is not trusted.
Hope this helps.
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note: perhaps you can change the subject of the first post to "Questions about boot chainloading with grub and old bioses".
When grub "chainloads" (boots another boot loader) with old (legacy) bios, it means that grub will attempt to load into memory and execute the contents of the first sector of the designated boot disk (i.e. USB pen drive) .This is an old bios computer. And yes, I can start an os on an usb stick with F12.
I do not need the usb menu entry in grub but I just want to learn more about grub.
You can find here the source code for the chainload command (from Debian Unstable, in this case):Grub will check the two byte signature (usually 0xaa55) of the boot loader. Then, after this check, the computer will execute any arbitrary code loaded from the first sector of the chainloaded disk.
That's why it's a possible vector for the spread of computer viruses if the content of the disk is not trusted.
Hope this helps.
--
note: perhaps you can change the subject of the first post to "Questions about boot chainloading with grub and old bioses".
Statistics: Posted by Aki — 2024-12-08 12:46 — Replies 4 — Views 144