After a board issue (see topic https://forum.mangoh.io/t/cannot-access-mangoh-yellow-wp7702/4848/27) I think there is a problem with the
swiflash command and its
-r option for recovery mode. With fw R12, this tool doesn’t work, I had to downgrade to R11 to be able to use it.
According to the release note of fw r12, QTI9X07-2870 is to fix userapp partition being erased which is security hole.