i tried according to the tutorial to unbrick the 300m via uboot using all available bin-files.
On each attempt the answer via uboot-Website is
Something went wrong during update Probably you have chosen wrong file (too big or too small) or you were trying to update ART on device with unknown FLASH type (and size) which is not allowed. Please, try again or contact with the author of this modification. You can also get more information during update in U-Boot console.
How can i access the uboot console?
PS The s/n is fbb10d28178d04b6