Espruino keeps disconnecting

Hello, I have a problem with Espruino Pico on Mac.
When I plug it in, red light flashes and then nothing flashes.
When I connect espruino tty.usbmodem1 it connects and after a while it disconnects.
When I want to connect it again, connection options state tty.usbmodem2 and again disconnects.
I tried to reflash the firmware (with success) but still the same.

Sometimes it writes this log:

Connected
>es from flash...
>Console Moved from Serial1
>
=undefined
>echo(0);
<<<<<{"VERSION":"1v81","BUILD_DATE":"Oct  8 2015","BUILD_TIME":"16:03:41","GIT_COMMIT":"8e1efcf898350a290242d732631be15c36f53381","BOARD":"PICO_R1_3","CHIP":"STM32F401CDU6","CHIP_FAMILY":"STM32F4","FLASH":393216,"RAM":98304,"SERIAL":"63004700-13513430-36363435","CONSOLE":"USB","EXPORTS":{"jsvLock":182749,"jsvLockAgainSafe":182737,"jsvUnLock":182713,"jsvSkipName":120321,"jsvMathsOp":209729,"jsvMathsOpSkipNames":277173,"jsvNewFromFloat":209961,"jsvNewFromInteger":210029,"jsvNewFromString":124953,"jsvNewFromBool":209985,"jsvGetFloat":203841,"jsvGetInteger":204657,"jsvGetBool":204105,"jspeiFindInScopes":210601,"jspReplaceWith":135865,"jspeFunctionCall":115713,"jspGetNamedVariable":140209,"jspGetNamedField":229317,"jspGetVarNamedField":228953,"jsvNewW
Disconnected
> 

Can you help me

It looks like there's some USB data connection issue (it seems like USB power is connected fine).

Please can you take a look at the back of your Pico and see if the PCB is scratched such that you can see copper?

If you're using one of the white Apple Extension leads, the 'spring' they put on the back of the lead tends to dig into the back of the Pico and can short out one of the USB data connections.

If that's it, the fix is quite easy:

• Use a non-Apple extension lead. Everyone else uses one with two leaf springs that don't scratch the PCB, and won't cause problems with the existing scratch.
  
• You can cut the offending track on the Pico (it's not needed) and you can then keep using it with whatever extension lead you want.
  
  

If that's not it, it'd be worth cleaning the contacts on the Pico (ideally with some kind of alcohol), and maybe trying a different extension.