Recently I procured two used Snapdragon Flight boards on ebay. One of the boards worked like a charm. The other one seemed to work albeit in a fragile manner. Upon further inspection I noticed that the IMU readings were erroneous (high acceleration values along x and z axis with the flight controller sitting still on a flat surface). Preliminary research on this forum and QDN revealed that certain Qualcomm Flight boards were deemed ‘faulty’. I decided to use the IMU onboard a Pixhawk as the source of inertial data with the Snapdragon flight board acting as the companion computer doing Visual Inertial Odometry and Pixhawk as the flight controller. The results were pretty decent. Here is a short video demonstrating snap_vio with inertial data from Pixhawk:
If someone is facing similar issues, I hope this helps you.
Also if there are better ways to go about this, I am open to suggestions. I am planning on buying an off-the-shelf MPU9250 IMU with a breakout board and using one of the serial ports on Snapdragon Flight for reading data with driver running on the DSP onboard.
Thank you @JulianOes for pointing me to DSPAL.