Dear Forum Members,
I've used an Arduino Mega as a serial datalogger and it has been working well. My serial message to be received is longer than the default 64 bytes, so I increased the buffer size to 256 (SERIAL_RX_BUFFER_SIZE in HardwareSerial.h 64 -> 256) with success following these instructions in:
However today I fixed a bug on the sketch, uploaded the new version and the received message was truncated back to 64 bytes. When I opened the Arduino IDE to do the fix I ran suggested updates to boards and libraries. I cannot remember anymore which updates these were and don't know how to check. I assumed that some of these updates had overwritten the HardwareSerial.h and my changes but no, they were still there.
I check from the sketch code the value of the SERIAL_RX_BUFFER_SIZE and it gives me 64 instead of 256 I've inserted to HardwareSerial.h. Changing SERIAL_RX_BUFFER_SIZE to any value in HardwareSerial.h has no effect.
After extensive poking and Googling I'm still clueless how to debug. Please advise.
EDIT: My OS is macOS Sierra 10.12.5 and IDE version 1.8.2