On Sun, 07 Feb 2016 13:10:16 +0000, Rainer wrote in message
<87h9hkmzt3.fsf@???>:

> Arnt Karlsen <arnt@???> writes:
>
>
> [...]
>
> >> > /sys/firmware/ and everything in it is mounted rw on my Gigabyte
> >> > legacy board with Devuan installed.
> >>
> >> That's true on my non=efi system, too, but it has
> >> no /sys/firmware/efi.
> >
> > ..can an efi board set up with legacy boot and running e.g. sys-v,
> > be tricked into bricking itself e.g. by reading an "ad" flash movie
> > off a web site and writing it into a new bad /sys/firmware/efi and
> > then "try" a kexec reboot? Etc?
>
> As far as I remember, I'm using an EFI-capable system in legacy
> mode[*] and the efivarfs module can't be inserted into my kernel.
> It's rejected with
>
> ERROR: could not insert 'efivarfs': No such device
>
> But this may be different on other systems and there's reportedly
> also a /sys-based older interface for accessing the EFI variable
> service. It should be possible to test this with
>
> modprobe efivarfs
>
> one could also remove the module (mine is called
>
> 4.5.0-rc2-net/kernel/fs/efivarfs/efivarfs.ko

..these are the fairy tales we are told nowadays.

..can a Devuan box be bricked etc with such EFI/systemd
type stunts using _other_, non-EFI, non-systemd names???

> ) or compile a kernel without support for the efivarfs (File systems/
> Pseudo filesystems/ EFI Variable filesystem) or without any support
> for EFI runtime services (Processor type and features/ EFI runtime
> service support)
>
> [*] I installed that by taking the disk out and connecting it to my
> former work computer, followed by copying the old system and then
> switched everything off which looked unfamiliar/ fishy during first
> boot of the new one without paying much attention to that.

..sounds familiar, I have a laptop disk running in its 5th
machine, online with "wlan4"... once I yank "eth2"... ;oD

--
..med vennlig hilsen = with Kind Regards from Arnt Karlsen
...with a number of polar bear hunters in his ancestry...
Scenarios always come in sets of three:
best case, worst case, and just in case.