JetPack 4.4 on AGX Xavier provides only black screen with blinking underscore

The SDK manager works fine saying flashing the OS is succesfull but the device AGX Xavier only shows a black screen with a blinking caracter on the left … No way to initiate nor complete the ubuntu configuration required to install the rest.
On reboot attempt, the Nvidia logo pops up … but then the black screen with blinking caracter comes again … Help please !

Solved, sorry … For the ones with the same issue : FORMAT your SD card before flashing !
Multiple re-flash did not work but after formatting all went fine …