February 8, 2026
Secure-ish Boot, meet chaos
Exploiting signed bootloaders to circumvent UEFI Secure Boot
Secure Boot busted? Tinkerers rejoice, Apple fans smirk, Microsoft gets blamed
TLDR: An open-source boot disk lets people run any system even with Secure Boot on, by leaning on already-signed parts. Commenters split between blaming sloppy vendors and Microsoft, demanding user control, and praising Apple’s tighter approach—showing the PC’s “secure” startup isn’t so secure and why trust truly matters.
Think the “Secure Boot” lock means your PC won’t run anything shady? The community is buzzing over Super UEFIinSecureBoot Disk, a DIY boot disk that slips past the lock by piggybacking on already-signed parts. In plain English: it uses the Linux startup tools “shim” and GRUB (the thing that loads your system) to make the computer accept almost anything—even if it’s not signed. Handy for rescuing locked laptops, spicy for security.
Then the comments explode. ronsor argues the real problem is vendors shipping sloppy boot code and says verifying every piece on the sprawling PC platform is a nightmare. Bratmon drops the meme of the day: Microsoft’s dream of locking out Linux fizzled because an antivirus partner wrote bad code—so “Linux survives on crappy AV.” bri3d pushes back on the claim that PCs only trust Microsoft’s keys, noting many motherboards let owners add their own, and stirs license drama over Microsoft’s refusal to sign GPLv3 software. mjevans calls for empowering hardware owners, not locking them out, while charcircuit throws an Apple-shaped grenade: the PC’s security is a fragmented mess, and Apple’s tighter garden looks safer.
The vibe? Secure Boot becomes Secure-ish Boot, with the crowd split between “give users control” and “please, just make it actually secure.”
Key Points
- •Linux distributions use shim to support certificate-based updates and to run GRUB2 in Secure Boot environments.
- •Red Hat’s GRUB2 patches block several functions under Secure Boot to prevent abuse.
- •GRUB’s chainloader uses an internal PE loader and shim-based validation to load files trusted by shim but not by UEFI.
- •Two bypass methods are described: a modified GRUB without verification or a custom pre-loader that hooks UEFI file authentication; the latter is preferred.
- •Super UEFIinSecureBoot Disk modifies PreLoader to allow all binaries, enabling boot of untrusted EFI files under Secure Boot with a defined multi-stage disk architecture.