Installing OpenWrt on Cisco Meraki MR18 in 2023 JTAG

This tutorial is still actual but missing some point that was necessary for me:

  1. First of all good GND connection and VCC on JTAG port , separated from UART (serial).
    On JTAG I propose pin 14 from Meraki (VCC) connect directly to VCC 3,3V on Raspberry PI (pin 1), pin 2 (GND) on Meraki to pin 25 on Raspberry.
  2. Fresh install of Raspbian without GUI, and after configuration disconnect unnecessary USB devices ( keyboard, monitor etc.)
  3. I could halt process and send firmware using first iteration of Raspberry PI ( rev.B) but cannot resume. When I changed to Raspberry Pi 4 - everything worked like a charm.