In addition to what @koburzasty gave (which is sort of the master download search tool), here is some additional information for your specific device based on the current software/tool releases.
JetPack is a front end to the driver package plus sample rootfs for flash. JetPack is also a tool which can install extra software on both the Jetson and PC. The micro-USB cable is used for flash, wired ethernet is required between Jetson and host PC for extra packages. You can use the extra package steps at any time if you uncheck flash. JetPack requires Ubuntu 14.04 or 16.04 on the host, but if you flash and don’t install extra software you can simply download driver package plus sample rootfs and flash on command line.
Flash itself uses only the micro-USB cable and doesn’t care about ethernet. The cable must be micro-B at the micro end. Cables on the market which are listed as charger cables often “sort of” work, but then fail because of low quality (these cables are typical of what comes with a smart phone for charging…these cables definitely have a lot of quality variation). If your Jetson is in recovery mode (holding down recovery button while either starting or holding down the recovery button with a tap of the power reset button) your host will see the TX1 via “lsusb -d 0955:7721”. You can test recovery mode whenever you want because this doesn’t actually change the Jetson, it just puts the Jetson in a mode where a custom flash driver understands the hardware. Even a cheap cable will usually show lsusb output for a recovery mode Jetson, but many cheap “OTG” cables will fail signal quality when running at USB2 speeds during the middle of the flash.
Extra packages use wired ethernet and the micro-B USB can be removed if only working on extra packages.
The most recent version of L4T for a TX1 is R28.2.1. The most recent JetPack version (which would provide L4T R28.2.1 during a flash or add packages compatible with R28.2.1) is version 3.2.1.
The R28.2.1 URL:
The JetPack3.2.1 URL:
Side note: Many people try to use a VM for host. The rarely works, and if you do use a VM, then you’ll have to do some work to avoid losing contact with the Jetson during a flash or other install. Unless you have to use a VM don’t. Command line flash has no requirement other than 64-bit desktop PC Linux. JetPack has specific Ubuntu PC requirements.