I took out the battery cover sheet of the remote, and even changed batteries. Bittle will not respond to the EQ to enter calibration mode. I was able to enter the calibration mode using the USB dongle though.
I might have accidentally pressed a bit on the infrared receiver while installing the board in the case, but I opened everything up, and the infrared sensor still seems correctly soldered on.
Is there any way to debug this? Alternatively, is there a way to control Bittle without either the Remote or serial USB connection to laptop?