TX2 not able connect with Ethernet cable after installing linux image

Building the massflash blob with ONLINE method requires:

  • Set up a X86 Linux host as the signing host'' in safe location. See L4T_quick_start_guide.txt’’ for detailed host setup.
  • If and only if secureboot is required, take extra steps:
    See Installing the L4T Secureboot Package'' in README_secureboot.txt to install secureboot package. See Generating the RSA Key Pair’’ in README_secureboot.txt
    to generate the RSA Key-pair.
    See ``Preparing the DK(KEK)/SBK/ODM Fuses’’ in README_secureboot.txt
    to prepare the DK(KEK)/SBK/ODM keys.

Hello bro where can i got the files like L4T_quick_start_guide.txt;README_secureboot.txt which requirement by the massflash ?now im in the Jetpack4.5.1