Twoway radio with U-Blox G6010-ST not working?

[oh2ftu]

Hi there.
I've got a two-way radio (let the make and model be a secret for now) that utilizes an U-Blox G6010ST chip for GPS.
The chip is not detected. No schematics are available for the radio, neither access to any debugging.
It's in a QFN56 package, so attaching probes can be a bit daunting.
Here's a link to a datasheet.

What I've been able to deduce so far:
- Voltage is present on most VDD-pins, except VDD_C0 and VDD_C1 (these are internally generated?)
- The crystal/oscillator seems bad -> this has been swapped, no change
- TXD1 pin seems to be high all the time (can be normal?)

I might be able to post a picture tomorrow of the general layout.
I've swapped the GPS chip from another radio, but I fear I might have cooked it. The symptoms are the same however.

Any ideas what I should check? I do have a scope and DMM but it has "been a while" since I last did any debugging like this. Actually, I've never gone this deep.