I’m trying on the same version of the toniebox than you guys and also having the same issues.
My setup are 0ohm resistors instead of the Tag-connect connector and a 3.3V USB-UART adapter which has DTR,RX,TX,VCC,CTS,GND pins. First I tried to do as described at Debug port | Toniebox Hacking , with toniebox contact #3 (VCC) bridged to #9 (SOP2), and #4 (RST) connected to USB-UART DTR, using the tool with --reset dtr, but the tool times out waiting for ack and the toniebox just becomes unresponsive until it’s power cycled.
Than I noticed that - USB-UART lights up even when its USB port is not connected to the PC (it should only receive power from the PC, right?) - if I don’t connect the toniebox to USB-UART, but simply bridge its #4 (RST) to #5 (GND) for a moment, it restarts with the normal startup sound; however if I keep bridged #3 (VCC) to #9 (SOP2) while resetting attempt, bridging #4 to #5 causes only short random fluctuation of toniebox LED brigtness and it becomes unresponsive until it’s power cycled. - accidentally I discovered that if the device contacts #2 and #3 are swapped (#2 used as VCC and #3 as RX), then the tool actually causes the toniebox to reset, and it plays some unusual beep sound (not random, smth like PC POST sounds) together with the normal startup sound; and the tool doesn’t time out immediately but displays this:
2025-04-18 16:22:35,356 -- Connecting to target...
2025-04-18 16:22:39,400 -- Connected, reading version...
2025-04-18 16:22:50,135 -- timed out while waiting for ack
2025-04-18 16:22:50,136 -- Could not connect to target: No ack for packet opcode=0x2f
I have not read anywere on the board about this Beep sounds before the startup jingle, and thought that it is the sign to be in the UART mode, but now I am not very sure any longer, does anyone of you also know the beep sounds, and how I can identify that the box successfully is in the UART mode.