There is a proposal to add it to the documentation page on connecting the console UART is another option. Connection using three wires (without connecting the supply line VCC). When connecting the console UART, you can use a simplified version with three wires. In this embodiment, the power running as usual , from an external power source. The console UART is used only for reading data and management. This will allow you to control the system behavior which requires significant power supply voltage for the periphery. I checked this option connect to your instance of VIM. Everything works - data output and control works. You can stop the download process and set\change variables from u-boot. By the way, now activated multiboot through the console UART.
Thanks for the feedback. We have done the work.