Flashing patterns
Without logs for the 4- | 6-LED flash modes it is not possible to say - I know it is repetitive but
Common mishap for 4-LED not working is faulty USB drive and/or incorrect formatting of the USB drive, e.g.
Cannot say for the 6-LED method since being a recent introduction and currently only available for that specific board revision.
Which could explain the matter.
There could be three potential issues with u-boot
- the environmental variables got somehow borked - which you could try to reset to default through the 5-LED ssh connection with
fw_setenv bootcmd 'env default -f -a; saveenv; reset'
and then try the 4-LED medkit again. - u-boot image got corrupted, though it seems unlikely since the u-boot rescue shell works apparently. It would be recoverable Omnia - Turris Documentation but requires UART serial cable/console. Also the u-boot image that shipped with your board does not seem available for public download - only the older version which would work with your board but lacking those 5- | 6-LED modes
- MTD partition table is corrupted, though it seems unlikely since the u-boot rescue shell works