Yes , both modules on their own work fine on slot 1. And both modules give blue screen on slot 2.
To add, both modules were in the laptop for over 5 years but been having problem recently, after tests narrowed down to faulty memory slot.
Yes I know it won't be cheap to repair and may be not worth it, m'board will be expensive. Shame it's i7 laptop.
The cheapest repair option to try is to take it a repairer and ask just to re-solder memory slot in case of dry joint.
4GB in one slot is too slow. I wonder if 8GB module in slot 1 will work?