> Did you really do this “guix pull”?  Because it is…
>
>> - guix system init ... /mnt 
>> - reboot
>>
>> Now on my fresh system, the only Guix available is the one from the USB
>> stick, namely 1.2, and not the one from my channels.
>
> …in contradiction with this.  So bug?

It's not a contradiction.

> In conclusion, the problem here does not seem cloning the repo, but
> fetching all the substitutes twice.

There is a misunderstanding: the Guix live system is not the same OS
(nor the same store) as the installed system.

-- 
Pierre Neidhardt
https://ambrevar.xyz/