Leonardo Gone Mad

Development Tools IDE 1.x
1

i had recent problems with my leonardo :- LEONARDO USB PORT NOT WORKING - Installation & Troubleshooting - Arduino Forum
so i had flashed the leonardo bootloader on my leonardo using my uno as ISP !
so , what i did was , connected Leonardo to UNO , and sucessfully uploaded the firmware !
today , i was able to install drivers for leonardo , and sucessfully alott it a com port !

then , when i tried to upload the blink code :-

Arduino: 1.6.5 (Windows 7), Board: "Arduino Leonardo"

Sketch uses 4,788 bytes (16%) of program storage space. Maximum is 28,672 bytes.

Global variables use 151 bytes (5%) of dynamic memory, leaving 2,409 bytes for local variables. Maximum is 2,560 bytes.

processing.app.debug.RunnerException: Couldn't find a Board on the selected port. Check that you have the correct port selected.  If it is correct, try pressing the board's reset button after initiating the upload.

	at cc.arduino.packages.uploaders.SerialUploader.waitForUploadPort(SerialUploader.java:245)

	at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:128)

	at processing.app.debug.Compiler.upload(Compiler.java:165)

	at processing.app.Sketch.upload(Sketch.java:1167)

	at processing.app.Sketch.exportApplet(Sketch.java:1141)

	at processing.app.Sketch.exportApplet(Sketch.java:1113)

	at processing.app.Editor$DefaultExportHandler.run(Editor.java:2380)

	at java.lang.Thread.run(Thread.java:745)

Couldn't find a Board on the selected port. Check that you have the correct port selected.  If it is correct, try pressing the board's reset button after initiating the upload.

  This report would have more information with
  "Show verbose output during compilation"
  enabled in File > Preferences.

that was the error , then my leonardo lights started flashing ! and the Tx Rx led's went Mad !

2

maybe it's too late to answer but this might help someone else
arduino leonardo is very fragile and uploading the wrong code might lead to problems like not being able to upload to it again. I had the same problem as harslu8 and this fixed it for me:

1-first of all you should have avrdude installed on your computer(I'm not going to explain how to install avrdude here because there a lot of tutorials on the web on how to install it)

2-connect your programmer to your arduino leonardo. I used usbasp programmer and an avr standard 10pin programming cable for this fix. you can use any other programmer just make sure to change the programmer option in the code below to match your set up.

3-start cmd(or bash if you are on linux)

4-type in:

avrdude -c usbasp -p m32u4 -U lfuse:r:low_fuse_val.hex:h -U hfuse:r:high_fuse_val.hex:h

5-if everything is connected correctly you should get this response:

   avrdude: AVR device initialized and ready to accept instructions

   Reading | ################################################## | 100% 0.05s

   avrdude: Device signature = 0x1e9587
   avrdude: reading lfuse memory:

   Reading | ################################################## | 100% 0.02s

   avrdude: writing output file "low_fuse_val.hex"
   avrdude: reading hfuse memory:

   Reading | ################################################## | 100% 0.02s

   avrdude: writing output file "high_fuse_val.hex"

   avrdude: safemode: Fuses OK

   avrdude done.  Thank you.

6-go to GitHub - sparkfun/SF32u4_boards: Support files for SparkFun's 32u4-based Arduino-compatible development boards. and download Caterina-promicro16.hex file

7- copy this file to c:\users(yourname)

8- in cmd type:

avrdude -c usbasp -p m32u4 -U flash:w:Caterina-promicro16.hex

9- your done!
credit and more info:Installing Arduino Bootloader on an ATmega32u4 · electronut