The exact same HM-10 would not work on the Arduino Uno but it works on the Nano with the exact same code and wired to the same pins.
I have tried swapping out the HM-10 to another one to rule out a faulty HM-10 even if I do not think it is faulty as it works on the Nano.
I have also tried swapping out the Uno in case it is faulty. I've also used the SoftwareSerialExample to send AT commands and it returns OK on the Nano but not on both my Uno.
Arduino > HM-10 (Baud 9600)
5V > VCC
GND > GND
Pin 8 > TxD
Pin 9 > RxD
I have tried both SoftwareSerial and AltSoftSerial with the same baud rate as the HM-10.
I am out of ideas and explanations as to how this can happen.
Anyone care to offer any insights? Thanks