yellow brake and service error code issue

[2010R55S]

I own a 2010 R55 S that I recently replaced the rotors, pads, and did a brake fluid flush the old fashioned way.
Even though the brakes feel amazingly precise, I'm still feeling a slightly spongy pedal.
I have a YELLOW brake warning icon on the tach, even though everything seems ok besides the slightly spongy pedal.I took it to the dealer, and they couldn't find why the yellow light is on. After a cursory inspection of the reservoir, they informed me they'd need to dig into it to try and ascertain the problem. I typically do all my own service, and have had issues with less than accurate dealer repairs with really high service charges. So, I'm wondering if anyone out there knows if the warning light, and yellow lift icon when I first start the vehicle is related to the slightly spongy pedal, even though the brakes seem to work just fine?

Wondering if a failure notification would pop up, I hooked up my OBD2 reader and got a misfire in cylinder 2 alert. I replaced all the coils as I have a lifetime guarantee from AutoZone.
It runs fine but I'm still seeing the P0302 alert.

I plan to buy a pressurized brake bleeder device, because my friend's pumping the pedal doesn't seem to be sufficient.
Any suggestions on which one to get that will screw on to my reservoir, and not cost
a ton of money?