how do you control Alert behavior on J2ME phones?

Question

I'm testing my midlet on 2 different Nokia model phones: 7210 Supernova and 6600 Fold.
Both are S40 5th ed SP1, still I get a different behavior with the alerts and I was wondering whether there is a way to fix that.

At various times my MIDlet beeps and puts up a self-dismissing Alert for n seconds (meaning it goes away after n seconds unless the user dismisses it earlier).

If that happens after the phone goes into screen saving mode (darkens), this is what happens:

• on the 7210 Supernova, the screen lights up, you see the alert, and if you don't touch it it dismisses itself after n seconds and you can see the background screen - this is the desired behavior.
• on the 6600 Fold, you hear the beep, but the screen remains dark. If you now press some button the phone lights up, but only then it displays the alert. The rest is similar. But this is problem because the whole MIDlet is at a stop until the user hits a key.

So I can fix it by not displaying this alert on phones that behave like my 6600, but I still want it on phones that behave like my 7210. Is there a way to check for this programmatically? what do you check for?