FEL mode unstable - what could cause this?

[Jurrie Overgoor]

Hello everyone,

I am trying to use FEL mode with a F1C200s. Other people (owning the same device) report everything works fine. But for me it is very unstable. Sometimes the sunxi-fel command correctly detects the chip:

❯ sudo sunxi-fel --list --verbose
Warning: no 'soc_sram_info' data for your SoC (id=1663)
USB device 001:015   Allwinner 0x1663  

But when I run the command again one second later, I get:

❯ sudo sunxi-fel --list --verbose
libusb_open() ERROR -1: Input/Output Error

I have a Wireshark trace of a successful call, and of a failing call. They start identical. Where the successful call gets to the URB_BULK out/in messages, the failing call does a "GET STATUS" request/response. The response is -EOVERFLOW.

Reading online suggests failing hardware. I tried with three different cables, and cold rebooted my machine once.

Of course, the chip could be bad. But is there something else that I might try before calling it quits? Like, a powered USB hub? (I don't currently own one.) Or using USB 2 ports? (I suspect my machine only contains USB 3 ports, but the device is using USB 2 because it is under the "ID 1d6b:0002 Linux Foundation 2.0 root hub".)

With kind regards,

Jurrie

[Jurrie Overgoor]

On Saturday, September 4, 2021 at 9:50:56 PM UTC+2 Jurrie Overgoor wrote:

I am trying to use FEL mode with a F1C200s. Other people (owning the same device) report everything works fine. But for me it is very unstable.

[Snip]

Reading online suggests failing hardware. I tried with three different cables, and cold rebooted my machine once.

Of course, the chip could be bad. But is there something else that I might try before calling it quits? Like, a powered USB hub? (I don't currently own one.) Or using USB 2 ports? (I suspect my machine only contains USB 3 ports, but the device is using USB 2 because it is under the "ID 1d6b:0002 Linux Foundation 2.0 root hub".)

Apparently, it's my USB host controller. I tried using a different system which has USB 2 and USB 3 ports. Both port types work flawlessly.

However, that system is old, so compiling kernels will take a long time. I'll try using a USB 2 hub to see if that makes a difference.

With kind regards,

Jurrie