[07_uart_chainloader] Make chainboot only works if I power my RPi3 after status `[MP] ✅ Connected` about rust-raspberrypi-os-tutorials HOT 2 CLOSED

Hi, sorry for the inconvenience!

Unfortunately, it is hard to exactly tell where it goes wrong.

Due to the fact that it always works when you power the RaspberryPi through Micro-USB, the best bet is that your USB-Serial cable is not able to provide enough power to the RaspberryPi. In this case, anything can happen.
If it is not the serial cable that is the bottleneck, maybe its the USB port. You could try different USB ports if that changes something.

Anyways, your message makes me realize that with different people using different serial cables and computers, assuming that powering over the serial works for everyone doesn't scale. It is convenient, that's why I went for it originally, but it was clear that underpowering can be an issue.

I'll take an action item to change the tutorials so that they demand the Pi being powered with an officially supported external power supply. This will also require changes to the chainloader protocol.
But please don't wait for me, I hope to get it done during the upcoming holidays.

FYI, delays on the host-side are in the Minipush and Miniterm scripts (but I don't think they are the issue here):

• https://github.com/rust-embedded/rust-raspberrypi-OS-tutorials/blob/master/utils/miniterm.rb#L40
• https://github.com/rust-embedded/rust-raspberrypi-OS-tutorials/blob/master/utils/minipush.rb#L30

from rust-raspberrypi-os-tutorials.

Thank you so much for the quick answer and insightful answer! I certainly did not consider power to be an issue (very new to low level programming / interacting with hardware, so lots to learn).

Already checked the Scripts out earlier, because I wanted to understand the chainload protocol. So I tried to use CoolTerm and sending everything manually. Was quite interesting and certainly helped my understanding of what is going on, but didn't work in the end.

Since you mentioned it, enjoy your holidays! 😄

from rust-raspberrypi-os-tutorials.