coreboot VS docs

Why BIOS (did you mean UEFI?) when it runs the best boot loader, which is Coreboot¹. Many users would love to re-flash their bios/uefi for it, if it’s supported.

1: https://www.coreboot.org/

Coreboot is 0.6% C++.

NovaCustom ; some models come with Dasharo a coreboot distribution.

You can also use Mr. Chromebox Script to install Coreboot on your chromebook to get a UEFI BIOS on your Chromebook and then you can go an install either a linux distro or even Windows if you want. It's a pretty straightforward process and also reversable if you want to go back to just using ChromeOS.

Some models are available with Dasharo a [coreboot]https://www.coreboot.org/) distribution.

why no haswell_ult_dmi_registers for broadwell? in https://github.com/coreboot/coreboot/blob/master/util/inteltool/pcie.c

use croshfirmware.sh from https://github.com/coreboot/coreboot/tree/master/util/chromeos

There may be other protections to restrict SPI flash access for security reasons (so you might not be able to flash your custom firmware in the OS), but worst case you can use a HW flasher (or maybe USB flashback). Still, this doesn't address the elephant in the room - platform initialization code might be open-sourced, but that isn't everything. You'll still need to figure out the board-specific stuff (the Super I/O chip, chipset GPIOs, other peripherals, etc.). Using coreboot as an example, Intel provides the Firmware Support Package blob to handle platform initialization. I think AGESA is somewhat similar to this, though Intel publicly releases the binaries for use in coreboot/etc. Thanks to the FSP, coreboot has support for recent Intel chipsets. However, there is only support for two recent consumer boards: the MSI PRO Z690-A WiFi DDR4 and DDR5.

does anyone know what is https://github.com/coreboot/coreboot/blob/b12caef23bc1b29c2e658f2b728cc4beac1e62b9/src/northbridge/intel/haswell/vcu_mailbox.c

Download crosfirmware.sh and run it from command line: bash crosfirmware.sh droid

Deterministic builds are available for some HW wallets. Major brands are audited by competitors and are under constant threat of being called out if they break the build process on any release. Bitcoin Core has a similar process called Gitian

If you feel comfortable following the Gitian build process, I would recommend giving it a try. You would setup a VM on your host (just like you are dong with TAILS), but you do so following the very strict process outlined here: https://github.com/bitcoin-core/docs/blob/master/gitian-building.md