Flashing SD card over USB

[pfeerick]

I'm developing my own PCB around the A64 and am currently using a Pine64 to develop my flashing procedure (want to have just eMMC on the board). For right now what I'm trying to do is flash a linux image to the blank SD card on the Pine64 using only the USB OTG port. It seemed like this was supported when I found Ayufan's USB Mass Storage, but I didn't get it to boot. The FEL interface becomes unresponsive, and the serial output shows us getting up to 'pmbus ready' I've got serial output from a few runs here: https://pastebin.com/tDve7G3t

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?

It seems to me that I must be missing something, because this functionality seems like something that must have been implemented somewhere, even if it hasn't been ported to the A64. Does anyone have any suggestions for how I can proceed from here?

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!