You’re trying to defend a flawed idea. Many known secureboot implementations can be simply disabled (patched out) because many of them planted their roots inside rewritable media (NOR or NAND flash). With a bit of prior knowledge, but doable.
Now consider typical scenario: typical Android phone, bootloader locked, unlocking done via website. Nice, if website still functioning. After, every fscking boot there is nag screen telling me I cannot trust my own fscking phone. Is this the secureboot? Nah, it’s trash acting like my enemy.
More, many secureboot implementations don’t provide a way to install my own keys. Sure, laptops and PCs mostly do, but it’s not guaranteed.
Next, secureboot implementations today are more like cryptolocks virus. Nobody knows effects when you actually try to disable it. I had a case when my friend brought me his laptop rendered unusable because he accidentally turned off that thing and it wiped volume master keys.
After all that experience I can’t but just say that all current secureboot is a big snake oil in computing.
By means of a token (for companies: usable for many devices), or optionally a longer pin, or a QR code, which are printed on paper (for private users: cheap, but for one device only). This key must be supplied independently of the “protected device” and may only be handed over to the designated owner.
I’m not interested in whether the owners/users understand the meaning and purpose, that’s the job of the PR departments of the companies that want to sell their devices “protected” by secureboot.
Would you buy a house that has a second entrance that you cannot control and that can be entered at any time by an unknown number of unknown people or groups of people who have the right to put in or take out any objects from your house?
These are copy-able.
Specialy, seller will help you to get “free” && install some thing for you .
Spy in comany will be a “fixer” to help employee to better “use” new devices.
So, You choose the house without the door?
The key of the door is got from house-seller. How did you confirm the key was not be copyed? Or, replaced? Or, put something in your new house?
Old idea.
Today they have new secureboot. If you rewrite the flash , your device will be a brick.
&& Secureboot not lock the device only. Some times it is locking data. If you unlock the secureboot, you will lost the data in same time.
These was choosen with that which is needed.
Did you mean, you can bought a locked mobile with “unlocked”?
Is this difference without secureboot?
How did you comfirm your new device is “clean”?
You should not think about others in your own thought.
Others is not responded.
I’m trying to clarify that secureboot, if it exists, shall be made as much transparent for end user, and standard as possible, being built over a common convention and be an open. What’s wrong with that?
This is nothing about standard.In some cases, read-and-certifying is enought.
Use signature algorithm like RSA to sign bootfile or datablock. when booting , let uplevel booter check the sign.
But, this have a lake is which is the top-level booter. You need a idea which can not be easy-changed bootloader to check the sign from once-powered.
So, CPU provider is ONLY OPTION. They (SiFive or Intel or AMD or LoongSon or Huawei oh… yes! Or StarFive) write the pub-key in CPU’s rom with a boot-app and let it be a toplevel booter.
After this , they use pri-key sign SPL/uboot to enable secureboot.