I inherited a MQX 4.2 project using the fsl_flexcan driver. Our application was running fairly well but during testing we rediscovered the CAN rx fifo bug (that dates back to 2015). I figured out a fix around this bug but seeing that MQX 4 is no longer supported, I recommended we upgrade to MQX5 rather than invest time on an unsupported OS.
I'm regretting this recommendation as MQX5, at least on the K60, doesn't seem like it has much support evidenced by taking almost 3 weeks after placing the order to get a set of files that don't even include the fsl_flexcan driver.
Q1) Is there an update to the fsl_flexcan driver that fixes the rxfifo bug?
I remember for TWR-K60F120M, MQX 4.2 is using the old flexcan driver, hardware rxfifo is not enabled. For TWR-K70F120M, rxfifo is enabled.
I would suggest you use Processor Expert routine that comes with Code Warrior. It should can generate CAN rx fifo code.