After the update, the device did not boot correctly!
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Then why when upgrading from version 6.42rc20 to version 6.42rc27 the router again ceased to give signs of life?No, only if older version was 6.42rc17 - 6.42rc24
As it was mentioned several times before in this topic. Upgrade happens on old version
6.42rc17 - 6.42rc24 are bad versions, so if you want to upgrade from these versions, use netinstall from the beginning.