Flashing SD card over USB

[ccben]

I haven't played with the USB OTG / FEL mode programming. ayufan and Xalius would probably be the best people to talk to (and maybe also tkaiser if he's online). My only suggestion look at this would be that perhaps power is an issue? When doing USB OTG loading with my rock64 using the rkusb tool, there is insufficient power on the USB lead to ensure the the write is successful, so I use a USB lead though an adapter that lets me switch the USB power off, and power the rock64 via the rPi header (as that is how mine is currently powered). Maybe this is what is causing your unresponsive system?

I tried this out and monitored the current draw from my USB A-A cable and my power supply. At 5V, whether through the Pi header's 5V or the Euler header's DCIN, the board is drawing ~80mA at reset and ~160mA from my bench supply after running 'make pine64_ums', and ~5mA from USB. It stops in the same place as in the original post. That 160mA is less than USB should provide anyway. Logs here: https://pastebin.com/NWNmvxGz

I also booted from an SD card into a really basic linux image (built with longsleep's build-pine-64 repo). With that, the board draws a max of about 270mA during the initial startup, and is at ~230 while idle at the shell prompt.

Based on that, it looks like power is not my issue; at least not at this stage.

Marcus is indeed right in pointing out that the boo order is:

Code:

boot-> check fel key pressed (yes)--> FEL mode (boot from USB OTG)
                         \  
                     (no) \
                           \-------> 1) try to boot from SMHC0 (SD card)
                                     2) try to boot from SMHC2 (eMMC)
                                     3) try to boot from SPI0 (SPI NOR Flash)
                                     4) FEL mode (boot from USB OTG)

but (there's always a BUT, isn't there)... do you have to have FEL mode? If you are trying to do some sort of image load... can booting from the USB work for you? If you get uboot booted, but there is no valid boot target on the microSD, it will look at the USB next. So the boot sequence would become SD card -> uboot -> USB. Is that any use to you?

I hope you do get your project up and running, especially if it will be an open source design/project... the more people that are working in this space, the more we all prosper.  More the merrier!

Our goal is to not require any additional hardware, other than a PC or smartphone that people will already have, and a USB cable. We're planning on a USB-C connector, so that would require an adapter or USB-C thumbdrive, too. Based on that, my understanding is that that will limit us to something with FEL mode.

And yes, this is an open-source project. Nothing released yet, I'm currently in the process of designing the hardware for our first rev using the A64, and am investigating this boot/flash process as I go, too.

Thanks!