@virtualchip: if your Rogers HTC Magic has Android 2.1 on it, then it has already been rooted, which means your warranty as far as dealing with Rogers goes) would be void.
I can't comment on using other ROMs (I haven't rooted yet myself), but if you can change the phone back to its original Android 1.5 build, you could then apply the Rogers 911bugfix update (Android 1.5) and then get the Over The Air (OTA) update to Android 2.1 which should be coming very soon. This "official" build might help, although you will likely not be able to root again afterward until someone cracks it.
This all depends of course on two things; 1. Can you get the phone back to 1.5; and 2. will you get the OTA update from Rogers since you are a Telus customer.
I suggest you ask this question in the Rogers forum here:
Rogers - Android Forums
There are a lot of Rogers users there with experience using the Rogers HTC Magic.