Restoring the bootloader on existing ce 9.2 installation running from emmc

Hello everyone. This is my first thread here, so please excuse any missing information. Feel free to ask me whatever is needed.

Back in 2021, I managed to install ce 9.2 on an old mxq pro 4k with s905 (1gb ram/8gb rom/100mbit lan). The device does not have a reset button, so I had to install a terminal app to its slooow android rom and run “reboot update” to make it boot from the sd card. Once it booted, I ran “installtointernal” and a few minutes later I had a fresh ce installation, which I later customised to my needs.
For reference, its device tree is

# cat /proc/device-tree/amlogic-dt-id gxb_p200_1g
the installation was done from the coreelec-arm-(version).img.gz, but I do not remember the dtb file I used. It was probably “gxbb_p200_1G_100M.dtb” and the tvbox was working properly for 2+ years.

And in 2023, when le released v11 and reintroduced support for a few old amlogic socs, I got that “shiny object syndrome” and I tried it from day 1, probably when it was on beta. Little did I know that the “installation” procedure would change the bootloader completely, making it impossible to boot from the emmc and boot only from sd or usb stick.

Since then, I tried restoring its original firmware in order to reinstall ce again, but I failed every time because the device gets disconnected in less than a second.

[ 26.557209] usb 3-2: new high-speed USB device number 2 using xhci_hcd
[ 26.695720] usb 3-2: New USB device found, idVendor=1b8e, idProduct=c003, bcdDevice= 0.07
[ 26.695739] usb 3-2: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[ 27.969026] usb 3-2: USB disconnect, device number 2

No matter the cable, the system, the usb ports or the version of amlogic burning tool I used, the result is always the same. This happens on usb1 only, as if all its other 3 ports are not working.

Is there anything I can do now? Thank you in advance.

p.s. Please excuse any delays in answering, because I am currently sick and recovery will be slow.