Jetson TK1 comes with Linux for Tegra (L4T) R19.2. This is fairly old, and defaults to using fastboot. The newer R21.4 is recommended, and uses u-boot (which in turn can boot custom kernels and such just via a text file edit). You can either install R21.4 directly via the driver package+sample rootfs, or use the JetPack 2.1 bundle. The bundle requires a host with Ubuntu 14.04, driver+rootfs works with any 64-bit Linux.
The 9-pin D-sub connector is set for serial console at speed
119200 115200, 8 bits, no parity, 1 stop bit ( 119200 115200,8N1).
FYI, the initial Jetson, as it ships, is technically just pure Ubuntu 14.04LTS, and does not have the nVidia-specific files installed which provide the special hardware access “goodies”. This includes video driver for X11. Within the home directory of “ubuntu” is the nVidia installer directory (I forget exact name and am not near my Linux host at the moment)…the run command there installs those files. But as I mentioned, this is only R19.2, you probably want to flash anyway after test driving it.
Please note that I am leaving out the “sudo” prefix to most commands below, but things like unpacking the sample rootfs and apply_binaries.sh require root authority for it to work correctly…so sudo or equivalent is required.
The typical set of instructions for a driver+rootfs type install is to unpack driver package on x86_64 host, go to the rootfs subdirectory, unpack sample rootfs, go back up one directory and run “./apply_binaries.sh” (this is equivalent of the nVidia-specific file install, but to the sample rootfs instead of directly on the Jetson). Then flash takes quite some time (an entire root file system is created)…connect the supplied micro-USB-B cable, put Jetson in recovery mode, and on host run:
flash.sh -S 14580MiB jetson-tk1 mmcblk0p1
This latter from R21.4 will install u-boot in place of fastboot.