USB ports not working and HDMI problem

I bought a Jetson nano 4gb version from thiss guy apparently he claims he worked I didnt test it out after I added few stuff to the board and remove the wifi adapter I check all of the ports of the back arent working but it turns on with green light and jumper added for the 5V. usb ports arent working and when I connect to TV nothing shows up on screen but it detects the HDMI. I already downloaded the jetson nano developer kit sd and flashed nothing seemss to be working please help.

Using the GUI to figure out if it is working is generally not a conclusive test. A bit of background…

Modern monitors are “plug-n-play” because the GPU can query the monitor for its capabilities. On HDMI this is done with the DDC wire (which uses the i2c protocol, and is actually powered by the GPU and not the monitor…monitors not powered up can still be queried). Two important details:

  • If the DDC wire is in any way interfered with, e.g., via a VGA adapter not having that wire or using a wrong early protocol, then there can be no automatic configuration. No DDC wire means no display.
  • The driver on the GPU of a Jetson only allows automatic configuration query over that DDC wire (the protocol is i2c with data format being EDID). No EDID data means no display.
  • If the EDID does work, but it asks for timings or resolutions beyond what the driver and hardware accept, it fails.

What does work, and is difficult to make it fail, is the serial console. See:

A full serial console boot log is extremely useful.

Also, the GUI frontend installer software is JetPack/SDK Manager. What actually gets flashed is Linux for Tegra (“L4T”, which is Ubuntu plus NVIDIA drivers). The two have their versions locked together. Which release are you using? You can see a list of releases here (finding one implies the other’s release version):

Documentation is available at those links, and is specific to that release.

I dont think I downloaded these the one I downloaded was the developer kit from this site

and im guessing I have to buy the serial console

On SD card models, if the boot content is compatible with the SD card release, then it will work. The problem is that the boot content is not on the SD card, and it isn’t unusual that one has to update the QSPI memory via the flash software in order to make it compatible with that release of SD card. This QSPI memory needs the JetPack/SDKM software in the above URL to be flashed (using the matching release as to that which created the SD card image).

You will probably end up flashing the Nano itself (not the SD card) to get that particular SD card to work. However, it is a very good idea to set up for serial console. This can tell you so much about boot issues that there is no other good substitute. Perhaps it is just a mismatch in boot release content versus SD card content, or maybe it is an issue with the monitor specs, or even both; serial console can tell you that. Other admin tasks may at times be best with a serial console as well, so I am guessing that buying the cable is a very good idea.

Incidentally, you could use an Ubuntu 18.04 host PC and flash the QSPI of the module itself (leaving the SD card alone) as a test even if you have the serial console cable on order.

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