That isn't anything inherent to the CPU architecture. We could have ARM (or RISC-V) systems that you could install arbitrary operating systems onto.

The danger is that the transition to another architecture is used as an excuse to not do this, even for devices that have historically been open.

"Danger" undersells it a bit - it's already happening, quite explicitly spelled out in Microsoft's legalese regarding Secure Boot. A lot of the Linux world was very afraid on the introduction of Secure Boot, as it was seen as the final anti-Linux coup-de-gras - Microsoft could, at their whim, simply turn off the ability to install Linux! This fear was widely mocked as hysterical. Now they have done exactly that, on all ARM devices that run Windows.

Offtopic, but

> coup-de-gras

Is funny. Gras (pronounced gra) means fat(as in animal fat, not a fat panda), and the real saying is coup de grâce (pronounced gras and means grace). For some weird reason English speakers pronounce coup de grâce improperly, skipping the s sound at the end ( funnily it's usually the French language which cuts sounds), including in movies (like Kill Bill).

That's fair, english speakers often make fun when the French mutilate our language as well :)

Er, yes... the greasy coup... meant it all along!

I firmly believe that this is their endgame on x86 too. The elevated Windows 11 hardware requirements had the effect of normalising hardware setups capable of end-to-end DRM, which is only a step to the side from Secure Boot restrictions.

Yeah I don't think it has much to do with security as it does securing hardware from competitors.

You can cast doubt on TPM/SecureBoot implementations with evidence, but it very much is real security controlled by the user with mokutil. We need more of this kind of security, that's controller by the user, if we're ever going to get away from locked bootloaders.

https://wiki.debian.org/SecureBoot

They give you the keys now. They could change that overnight if they mandate the same "Secure Boot only with a Microsoft key" that they mandated on early ARM devices. Don't be mistaken. They are very much the Don of x86, and when they choose to alter the deal, you'll be SOL.

That's why I consider alternative ecosystems (that don't have exorbitant prices) like RISC-V and Raspberry Pi to be critical to the survival of general-purpose computing. Once your ability to run on bare metal disappears (via Secure Boot or otherwise), you're in grave danger of simply not having physical hardware to convert new users.

I hope the regulations being discussed right now[1] pass and we can just call SecureBoot what it is instead of fearing what it might become (atleast on x86).

[1] https://www.congress.gov/bill/117th-congress/senate-bill/299...

A lot of people who have lived entirely in the x86 world are completely unaware that a single CPU architecture can have many, many, many different incompatible types of system architecture - x86 means a few sub-types of BIOS + UEFI-based PCs, while ARM, Power, etc have far more variance.

The fact that you can't install Windows on an ARM Mac is mainly a licensing issue, as in, Microsoft will not sell you an ARM license. Apple has said it's open to the idea of ARM Bootcamp and people have pretty successfully ran ARM Windows in VMs.

I wonder why anyone would want to? I thought you could do it on Pi4 for free so why not Mac? https://www.notebookcheck.net/Windows-11-can-even-run-native...

I don't understand the point you are making Pi4 is broadcom and it works.

This is not an architecture issue but ecosystem. Current PC/x86 systems have been built in open historically. ARM has no such baggage, they are free to build closed and incompatible systems which are awesome as long as you stay within the garden.

ARM is significantly more open than x86.

For "x86", read "the PC platform" - which is the thing that gave us modern general purpose computing, and we obsolete it at our peril.

> For "x86", read "the PC platform" - which is the thing that gave us modern general purpose computing, and we obsolete it at our peril.

Wasn't the Apple I the modern general purpose computer?

ARM popularised the concept of bootloader locking. I don't think so.

Has absolutely zero to do with either openness or ARM.

It certainly does. An architecture isn't just about the ISA, but the culture around it too. The culture around ARM mobile phones and tablets heavily emphasized bootloader locking, which accelerated its spread to x86 too - which works contrary to the notion of openness.

> The culture around ARM mobile phones and tablets heavily emphasized bootloader locking

Virtually all of which are user-unlockable. But keep telling me how unopen they are?

(BTW, those of us who actually want secure systems very much appreciate the fact that malware can't overwrite my boot sector without a hardware-level vulnerability.)

If its good they'll make a hack to unlock it. Have phones that were sold locked, so many security bugs that they are easily unlocked.

I am aware of exactly 0 ARM motherboard makers that make boards with socketed (read upgradeable) CPUs. I know they are made for PowerPC. I know there are tons of x86 ones.

For a while I bought motherboards with upgradable CPUs. I quit doing that after a while because by the time I wanted to upgrade, the newer chips required a new socket, I needed faster memory that the motherboard didn't support, etc.

I wasn't aware that it had to be socketed to be open?

I don't think this is an inherent property of the instruction set / CPU. Moreso the device manufacturer and whether drivers are supported.

> How easy is to replace the operating system on an ARM mobile device

Very easy if you have an Android phone :)

>Very easy if you have an Android phone Very easy if you have an Android phone from the correct manufacturer that and it's popular enough to have custom roms for it or you know how to port custom roms to other devices*

Nope, nowadays any recent-ish Android can receive custom ROM very easily, using GSI.

But the restriction is that many OEMs and/or carriers forbids bootloader unlock.

If you have Android, you have to have an excessive number of stars aligned just right for a successful OS replacement. On x86, the replacement involves toggling some firmware settings, rebooting, and using a point and click installer. On Android:

1. Have bootloader unlock available via official channels. If you are in the 1% with a supported phone variant, congratulations. Service box unlocks, while often possible unofficially, rarely result in a critical mass of developers that's needed for the next step.

2. Have a ROM ready to go. If lucky, it'll be Lineage OS. If less lucky, some unofficial build of Lineage OS with potentially some hardware not supported (but there's hope!). If you are really unlucky, the phone is so unpopular that a ROM developer hasn't taken enough interest in it to produce a usable ROM.

3. Flash the ROM, keeping all idiosyncrasies of the particular hardware in mind. Hope you got the right partition table/kernel/bootloader/ fragile fragment, because if you flash the one meant for GEX5546ab on a hardware that corresponds to GEX5546cb, you just killed your phone. Run through contingency procedures for unbricking the phone in case you need them.

4. Congratulations. You now have a firmware that works better than the factory OS, but they also happens to potentially not support small things like Bluetooth or the camera blobs. You may get support in 2-3 months, hopefully. Your secure enclave keys are also gone, so bank apps will be suspicious and Netflix will refuse to serve higher-quality content.

>1. Have bootloader unlock available via official channels. If you are in the 1% with a supported phone variant, congratulations. Service box unlocks, while often possible unofficially, rarely result in a critical mass of developers that's needed for the next step.

Untrue for most of the phones on XDA, S3 was the most popular android phone and came locked.

>2. Have a ROM ready to go. If lucky, it'll be Lineage OS. If less lucky, some unofficial build of Lineage OS with potentially some hardware not supported (but there's hope!). If you are really unlucky, the phone is so unpopular that a ROM developer hasn't taken enough interest in it to produce a usable ROM.

Luck to me is more than LOS, its the bare minimum, but I have gotten unlucky with non popular phones. Not hard to look at roms when you see if you should root or install custom bootloader.

>3. Flash the ROM, keeping all idiosyncrasies of the particular hardware in mind. Hope you got the right partition table/kernel/bootloader/ fragile fragment, because if you flash the one meant for GEX5546ab on a hardware that corresponds to GEX5546cb, you just killed your phone. Run through contingency procedures for unbricking the phone in case you need them.

You could just run Halium to run Linux with all drivers, or use chroot to have linux in it too. Safety that existed since 2012 prevented me from ever having a single issue like that, and I never bricked a phone with over 20 flashes.

>4. Congratulations. You now have a firmware that works better than the factory OS, but they also happens to potentially not support small things like Bluetooth or the camera blobs. You may get support in 2-3 months, hopefully. Your secure enclave keys are also gone, so bank apps will be suspicious and Netflix will refuse to serve higher-quality content.

This was occasionally true before 2017. All new phones have mainline linux support. https://www.computerworld.com/article/3306443/what-is-projec... https://www.xda-developers.com/android-project-mainline-modu...

Basically, if you spend 10 minutes looking up relevant information, buy a popular phone with good support and you will face 0 problems. You are making a mountain out of a molehill.

Yes you can on some, Apple's T1 was on x86 to prevent other OSes from installing. ARM isn't as open, RISC-V is, but don't worry x86 will still be staying in the way tha PPC, Amiga, and the ARM based on RISCOS stayed.

>Can you install Windows or Linux on ARM Macs?

ARM Windows sucks. I wouldn't even try, asahi can be installed (but I don't get why you would, all unix stuff works) https://asahilinux.org/about/