OpenSDA bootloader does not show up after reflashing firmware

[jyt_is_pyt]

Hi everyone,

I am very new to using Kinetis boards, having recently migrated from Arduino. It is unfortunate that my first post would have to be about troubleshooting, but here goes:

I bricked my OpenSDA bootloader (FRDM K66F) while trying to do a J-Link OpenSDA firmware update in Windows 10 using the drag-n-drop guides. I ended up purchasing a J-Link EDU in order to unbrick the bootloader (but I guess I might as well debug over J-Link), following the guides here: Freedom OpenSDA Firmware Issues Reported on Windows 10 . However, the chip is not recognized over USB. These are behaviours both exhibited in both Windows and Linux, at least on my machine. The bootloader worked fine before the update, however (Maybe I should have left the bootloader alone).

I am wondering whether I am missing parts of the bootloader, if the byte offset gone wrong, or some hardware issue related to my USB port, or some other unforeseen issue. Your feedback is appreciated.

[jyt_is_pyt]

UPDATE: I found some firmwares that enumerate over USB with the MK20DX128xxx5 chip. They show up under in my file explorer (both Linux and Windows) as a storage device. Problem is that they are not recognized by MCUXpresso, Keil, or IAR at all, and the RESET LED no longer lights up unless powered from the target USB port (MK66's USB port, not OpenSDA)

Also the recommended firmwares for my board (K66F) don't seem to work either in Windows or Linux, despite being what is recommended.

Firmwares found that enumerate over USB but not recognized by MCUXpresso:

#1 https://community.nxp.com/servlet/JiveServlet/download/1072946-1-435301/0244_k20dx_bl_0x8000.bin.zip 

#2 https://github.com/mbedmicro/DAPLink/files/713134/OpenSDA.2.2.Daplink.BOOTLOADER.for.K20DX.0x8000.zi... 

UPDATE 2: 

I found a workaround for this issue. It was quite a roundabout hack for me since I started noticing what certain firmwares did.

What I learned:

- For some reason, programming recent firmwares into the board does not work, had to use working firmware #1 (see above) as a base.

- Working firmware #1 shows up as MAINTENANCE over USB, while working firmware #2 does not (it shows up as DAPLINK instead). These have to be directly programmed by a debug probe.

- Since the board shows up as MAINTENANCE over USB, I was able to upgrade the firmware using drag-n-drop (tested both J-Link and DAPLink firmwares)

Its safe to say my issue is solved, though this is a weird one.

[disha_das]

We are able to see the Maintenance drive on using Firmware #1. We are using JLink.

Now, what FW should be dragged and dropped onto the maintenance drive. Can you please share the file.

[ErichStyger]

What debug firmware (V1.x, V2.x) depends on the board and bootloader you have flashed.

You can find the different files on the SEGGER web site:

https://www.segger.com/products/debug-probes/j-link/models/other-j-links/opensda-sda-v2/