Direct migration from 19.07 is currently not possible.

Gone due to
commit 45c84a11 ("ar71xx: drop target")

(cherry picked from commit a18510c0)

Gone due to
commit 45c84a11 ("ar71xx: drop target")

(cherry picked from commit bc09b7ec)

Signed-off-by: David Bauer <mail@david-bauer.net>
(cherry picked from commit 94249bfa)

Support for the device was (re)added in #2455
(merged as 94e04393)

(cherry picked from commit cd37fe5d60543a0af296f64880ca7047c681a82a)

Co-authored-by: Tom Herbers <mail@tomherbers.de>

Gone due to
commit 45c84a11 ("ar71xx: drop target")

Gone due to
commit 45c84a11 ("ar71xx: drop target")

Changed subtarget in between, similar change in
commit bed66fa2 ("ath79: move GL.iNet GL-AR750S to NAND subtarget")