You're allowed to import an X amount of EUR from a non-EU country. I think X amount differs per country. In NL it is 430 EUR. FWIW, Nokia N900 is worth more than 430 EUR.

In NL, for receiving packages outside of EU anything under 22 EUR is free to go, anything between 22 EUR and 150 EUR is VAT (+ clearance fee), anything over 150 EUR is VAT and customs tax (+ clearance fee). For other EU countries it most certainly differs, but expect similar constructions. It adds up rather quickly.

Your friend will receive item and either pays duties or not depending on State where he receives package. In your case you take it with you, and if you pay in cash that seems reasonably secure. Except somewhere some 500 USD were spend by you in cash.

If you weren't physically visiting he'd sent it to perhaps as 'gift' (which it actually isn't), and sends it insured or not. Without is risk. Either way, additional costs.

However, in both of these cases the product is sealed and new, and when it was bought by whom can be easily traced. It is bought in USA, and in one way or another you paid for it hence it was not a gift.

You're probably low profile but realize what you are doing in this case is commiting fraud, and publicly admitting a crime isn't the most wise move.

You also still have the problem of warranty, and the WLAN chip does not allow Ch 12 & 13.