[Tails-l10n] [de] questions, pre-review

hi,

I am almost finished with the news and security issues pages, but am
still unsure about a few translations.

Does anybody have any idea or opinion about:

* upgrade

I used the noun "Upgrade" but I can't write things like
"um up zu graden". What is the right word/phrase to use here?
Maybe "umsteigen"?

* freeze

Do people say "mein Computer ist eingefroren"?

* device

Can we use "Gerät" for device in the sense of DVD, USB stick, or SD
card? I don't like this, but also don't have a better idea.

Best,
sycamoreone