FEL mode repeatedly connects and disconnects. Is this normal?

[projek01]

Hi everyone,

Here is the backstory, I am an owner of a Xiaomi STYJ02YM vacuum cleaner robot that uses a Allwinner R16-J and a 4GB eMMC flash. Like many others, the latest firmware update bricked their devices and we have zero support/warranty outside of the intended original Chinese market.

My device is stuck in a bootloop and it seems like it is entering FEL mode for about 2 seconds, disconnecting for 3 seconds and repeating over and over. Is this normal behavior?

Device=ff.ff
[ 2733.131960] usb 3-4: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 2735.917395] usb 3-4: USB disconnect, device number 109
[ 2749.007512] usb 3-4: new high-speed USB device number 110 using xhci_hcd
[ 2749.155791] usb 3-4: New USB device found, idVendor=1f3a, idProduct=efe8, bcdDevice=ff.ff
[ 2749.155796] usb 3-4: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 2751.945094] usb 3-4: USB disconnect, device number 110

It is my understanding that there is a recovery partition on the eMMC. Is there anyway I can use the FEL mode to copy this recovery partition over to boot0 without having the .img available for Live Suit?

Thank you for your help in advance!

Regards,
Anthony

[olecom]

@projek01 at least FEL (by sunxi-fel tool) can be used to load u-boot and thus start the bricked/non-bootable system. Depending on u-boot features builtin, I guess eMMC can be accessed. But where it can get data to flash?

Or device can be booted from uboot and/or network into real OS image and then eMMC can be accessible as well:
https://github.com/zador-blood-stained/fel-mass-storage (taken from:
https://forum.armbian.com/topic/4241-flashing-image-to-emmc-via-fel/?do=findComment&comment=31615)

How and where to get properly configured u-boot and device trees for that hardware is another good question...

[projek01]

I gave up on mine. I couldn't get FEL mode to stay active for any more than 3 seconds at a time. By the time sunxi tools detected the vacuum, it would disconnect.

I even tried connecting to the 4 pin header next to the USB port via serial rx and tx but had no luck. It's either find a source to buy motherboards or I will have to bring the vacuum to China within the year.

[olecom]

Then it's an electrical issue, I guess, not software. Mine A20 stays in FEL mode for minutes before I compile and upload new U-Boot for it.

Multimeter, tester or oscilloscope could be helpful in identifying what (e.g. watchdog?) happens on chip's recovery and reset pins...
Similar vacuum info found in
https://github.com/dgiese/dustcloud-documentation/blob/master/rockrobo.vacuum.v1/techinfo.pdf from #294