In the last days I finally got some bits out of the Nokia N900’s modem on Debian without any properitary tools. For now it’s just the following information:
manufacturer: "Nokia"
model: "Nokia N900"
revision: "V ICPR82_10w08 25-02-10 RX-51 (c) Nokia"
But the most difficult part is probably done. My next plan was to get the modem connect to a mobile network, which requires an unlocked SIM card. Unfortunately ofono does not yet support SIM cards with PINs. Thus I had to find another way to get out how to perform this task.