Custom binary > Boot fails (Puck.js flash layout)

Thank your for your timely reply.

How are you flashing to the Puck?

Using the NRF Toolbox.
I'll try to erase 0x1f000-0x78000 by flashing an empty image

• 0x1f000 -> 0x73000 = Espruino
  
• 0x73000 -> 0x76000 = Saved Code
  

Isn't the Espruino section followed by free space for arbitrary usage?
Could moving the Espruino-free space boundary add issues?