It sort of works, I get a ping and a missing pong:

(254 is button node, 252 is repeater I turned off after the button node was started up)

64442 TSF:PNG:SEND,TO=252
64479 !TSF:MSG:SEND,254-254-252-252,s=255,c=3,t=24,pt=1,l=1,sg=0,ft=0,st=NACK:1
66488 TSF:CKU:FAIL

But no looking for a new parent.

I tried calling some functions I thought sounded like they would help me, without really knowing. I guess it is not functions that a user like me really should use?:

if ( !transportCheckUplink() ) {
  stParentTransition();
  while ( isTransportSearchingParent() ) {
    stParentUpdate();
  }
}

This starts what appears to be a new parent search, but it never completes:

151171 TSF:MSG:SEND,254-254-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
153180 !TSM:FPAR:NO REPLY
153182 TSM:FPAR
153219 TSF:MSG:SEND,254-254-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
155228 !TSM:FPAR:NO REPLY
155230 TSM:FPAR
155267 TSF:MSG:SEND,254-254-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
157276 !TSM:FPAR:NO REPLY
157278 TSM:FPAR
157315 TSF:MSG:SEND,254-254-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
159324 !TSM:FPAR:FAIL
159326 TSM:FAIL:CNT=7
159328 TSM:FAIL:DIS
159330 TSF:TDI:TSL
161333 !TSM:FPAR:NO REPLY
161335 TSM:FPAR

At this point I have started my repeater again, and I think it should also find either the gateway or another node.

I guess another way would be like this:

if ( !transportCheckUplink() ) {
   asm volatile ("  jmp 0"); // CRASH, BURN AND RESET
 }

It does the trick ... though it really bothers my developer-heart ;)

Sorry I haven't gotten back to you, been a busy week.

The MY_TRANSPORT_MAX_TX_FAILURES seems to do the job perfectly, I adjusted it down to 1 for the node, and resend the message a couple of times if it fails.

Thank you for your support :)

Also thanks to berkseo, your code also works for me, but I do prefer the built in way now that I know of it. Less code for me to write and maintain :)

@berkseo Great :) I am currently trying to figure out what my employers policy for open source contributions made in their employees spare time is, so I could make the pull request myself, but you beat me to it :(