Ensure that it's fully turned off by holding down the power button for ~20 seconds.
I've had it stuck with a black screen before a few times and after force-shutting it down that way and powering it back on tegrarcm recognized it.
To play devil's advocate, running a payload whose source is private is much more dangerous than running a homebrew application whose source is private. It's understandable they'd have less issue with DBI binaries vs Lockpick_RCM.
While it's good that more than one person is keeping Lockpick_RCM...
Great for folks that were wrapping up their titles (assuming they walk it all the way back and not just revise it slightly), but folks really ought to just stop using Unity anyway.
It feels like every year they make a new shitty move, and I personally wouldn't trust them not to continue that...
I haven't used Tinfoil before, but I imagine it won't throw any errors with an untampered XCI.
If you're only trying to verify it, you might try using NSC Builder, which can verify NSPs and XCI on PC:
https://github.com/julesontheroad/NSC_BUILDER
There probably won't be a soft mod like others have said, horizonOS is pretty solid by this point.
But on the bright side that has led to hard mods becoming easier and cheaper to do since that's the only option.
You can't convert an XCI to an NSP without failing signature checks.
(Not without Nintendo's private signing key, anyway)
If you're wanting to install your cartridge dump without an invalid signature warning, you'd be better off installing the XCI directly.
Iirc most installers support...