how to recover ATSAM3U2CA-AU(J-link ) nrf52840-dk jlink can't found

Question

hi all, 
 how to revert interface MCU ATSAM3U2CA-AU(J-link ) 
 
 when i plug in usb port to PC, DK board can't active .(PC can't detecting any USB Emulators) 
 
 check list: 
 LED5 led not turn on 
 measure VDD 2.99V and 5V 
 can use extra j-link to detect nrf52840 and program it . 
 as my view that is on-board j-link is erased .(i try serialization before) 
 
 how to recover ATSAM3U2CA-AU(J-link ) 
 
 Thanks a lot and best regards.

stevenlin · Answer

hi all , 
 i found this thread about how to Jlink OB or mbed. 
 https://translate.google.com.tw/?hl=zh-TW&tab=wT#view=home&op=translate&sl=auto&tl=zh-TW&text=As for firmware - as far as I'm aware the Segger firmware is not available for you to download and use in a 3rd party product. It's licensed to Nordic for use in their products. If you want to use JLink OB on your device you need to go talk to Segger and purchase it from them.