TAR unknown is how a live migration discovers who does not yet carry the applet. Retrying the same RAM command on those cards fails identically. Split the estate: cards that answer 09 go to install; cards that accept the TAR go to the migrate command. Confirm the TAR against TS 101 220 annex D and the vendor manual — vendor TARs vary and the manual wins. Decode the command packet to see which TAR you actually sent.
Usual cause
The card has no application registered against the Toolkit Application Reference you addressed. Either the TAR is wrong, or the application is genuinely not on that card, or it is present but not registered for the toolkit event you are using.
What to do
Verify the TAR against TS 101 220 annex D and the card vendor manual — vendor TARs vary and the manual wins. On a migration this code is usually informative rather than an error: it is how you discover which cards do not yet carry your applet, so treat it as a segmentation result and route those cards to the install campaign instead of retrying.
TS 101 220 annex D