# Check bootloader logs via UART
**URL:** https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053
**Category:** Jetson Xavier NX
**Tags:** uart
**Created:** [September 24, 2021, 6:17pm UTC](https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053 "2021-09-24T18:17:15Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@gokulnath136](https://forums.developer.nvidia.com/u/gokulnath136)
#### Post date: [September 24, 2021, 6:17pm UTC](https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053/1 "2021-09-24T18:17:16Z")
Hi,
I have a Jetson Xavier NX board, with which I have connected a USB-TTL Serial cable. The cable is [this](https://www.crazypi.com/USB-SERIAL-TTL-RASPBERRY-PI?search=usb%20to%20ttl&description=true) which has
- Red: +5V
- Black: GND
- Green: TxD
- White: RxD
and the chip that is used is PL2303.
Here is the relevant output of `dmesg | grep Prolific` on my host machine:
> [686342.604682] usb 1-1: new full-speed USB device number 62 using xhci\_hcd
> [686342.757633] usb 1-1: New USB device found, idVendor=067b, idProduct=2303, bcdDevice= 3.00
> [686342.757646] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> [686342.757652] usb 1-1: Product: USB-Serial Controller
> [686342.757656] usb 1-1: Manufacturer: Prolific Technology Inc.
> [686342.759409] pl2303 1-1:1.0: pl2303 converter detected
> [686342.760425] usb 1-1: pl2303 converter now attached to ttyUSB0
> [686386.176902] usb 1-1: USB disconnect, device number 62
> [686386.177183] pl2303 ttyUSB0: pl2303\_set\_control\_lines - failed: -19
> [686386.177197] pl2303 ttyUSB0: error sending break = -19
> [686386.177507] pl2303 ttyUSB0: pl2303 converter now disconnected from ttyUSB0
> [686386.177555] pl2303 1-1:1.0: device disconnected
I have connected it to J14 header on pins 3,4 and 7 on my board i.e white to 3, green to 4 and black to 7 as mentioned in the Developer Kit.
On the host PC, I am using minicom. I ran `sudo minicom`, which gave me the error: `minicom: cannot open /dev/modem: No such file or directory`.
Post that, I ran `sudo minicom -D /dev/ttyUSB0`, as that was the only difference in `ls /dev` when I removed or added the cable.
This gave me active terminal like this:
> Welcome to minicom 2.7.1
> OPTIONS: I18n
> Compiled on Dec 23 2019, 02:06:26.
> Port /dev/ttyUSB0, 15:13:21
> Press CTRL-A Z for help on special keys
I restarted my board, waiting for logs to show up here but I didn’t get anything.
The output for `dmesg | grep THC` on the board is:
> [1.542048] 3100000.serial: ttyTHS0 at MMIO 0x3100000 (irq = 47, base\_baud = 0) is a TEGRA\_UART
> [1.543422] 3110000.serial: ttyTHS1 at MMIO 0x3110000 (irq = 48, base\_baud = 0) is a TEGRA\_UART
> [1.544422] 3140000.serial: ttyTHS4 at MMIO 0x3140000 (irq = 49, base\_baud = 0) is a TEGRA\_UART
This is the result of `ls /dev/tty*` on my host PC:
> /dev/tty /dev/tty17 /dev/tty26 /dev/tty35 /dev/tty44 /dev/tty53 /dev/tty62 /dev/ttyS11 /dev/ttyS20 /dev/ttyS3
> /dev/tty0 /dev/tty18 /dev/tty27 /dev/tty36 /dev/tty45 /dev/tty54 /dev/tty63 /dev/ttyS12 /dev/ttyS21 /dev/ttyS30
> /dev/tty1 /dev/tty19 /dev/tty28 /dev/tty37 /dev/tty46 /dev/tty55 /dev/tty7 /dev/ttyS13 /dev/ttyS22 /dev/ttyS31
> /dev/tty10 /dev/tty2 /dev/tty29 /dev/tty38 /dev/tty47 /dev/tty56 /dev/tty8 /dev/ttyS14 /dev/ttyS23 /dev/ttyS4
> /dev/tty11 /dev/tty20 /dev/tty3 /dev/tty39 /dev/tty48 /dev/tty57 /dev/tty9 /dev/ttyS15 /dev/ttyS24 /dev/ttyS5
> /dev/tty12 /dev/tty21 /dev/tty30 /dev/tty4 /dev/tty49 /dev/tty58 /dev/ttyACM0 /dev/ttyS16 /dev/ttyS25 /dev/ttyS6
> /dev/tty13 /dev/tty22 /dev/tty31 /dev/tty40 /dev/tty5 /dev/tty59 /dev/ttyprintk /dev/ttyS17 /dev/ttyS26 /dev/ttyS7
> /dev/tty14 /dev/tty23 /dev/tty32 /dev/tty41 /dev/tty50 /dev/tty6 /dev/ttyS0 /dev/ttyS18 /dev/ttyS27 /dev/ttyS8
> /dev/tty15 /dev/tty24 /dev/tty33 /dev/tty42 /dev/tty51 /dev/tty60 /dev/ttyS1 /dev/ttyS19 /dev/ttyS28 /dev/ttyS9
> /dev/tty16 /dev/tty25 /dev/tty34 /dev/tty43 /dev/tty52 /dev/tty61 /dev/ttyS10 /dev/ttyS2 /dev/ttyS29 /dev/ttyUSB0
Is there anything else I should be doing?
I also tried removing ‘quiet’ from `/boot/extlinux/extlinux.conf` as mentioned in some issue, but it’s still not giving me any output on the host PC.
Any help would be greatly appreciated.
---
### Author:  [@WayneWWW](https://forums.developer.nvidia.com/u/WayneWWW)
#### Post date: [September 25, 2021, 9:54am UTC](https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053/2 "2021-09-25T09:54:18Z")
Hi,
> **[Jetson Nano & NX Style - Serial Debug Console - JetsonHacks](https://jetsonhacks.com/2019/04/19/jetson-nano-serial-console/)**
>
> The Serial Debug Console is the most basic way to be able to interface with your Jetson Nano & NX Style Developer Kit. All it takes is a magic wire!
Please make sure you are using the correct baud rate. Also, I don’t quite understand that you said there is no log on your minicom, then where did you dump those dmesg logs?
---
### Author:  [@gokulnath136](https://forums.developer.nvidia.com/u/gokulnath136)
#### Post date: [September 25, 2021, 10:02am UTC](https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053/3 "2021-09-25T10:02:28Z")
Thanks for the reply.
> Please make sure you are using the correct baud rate.
I checked the baud rate on minicom and this is what I found:
> Serial device: /dev/ttyUSB0
> Lockfile location: /var/lock
> Bps/Par/Bits: 115200 8N1
So I suppose the baud rate being used is 115200 bps. Is this not the correct baud rate? I saw the answer by Jerry [here](https://forums.developer.nvidia.com/t/how-to-use-uart-on-xavier-nx/174343), which mentioned the use of `picocom -b 115200 /dev/ttyUSBx`, so I thought the baud rate was correct.
> Also, I don’t quite understand that you said there is no log on your minicom, then where did you dump those dmesg logs?
Apologies if it wasn’t clear. I’ve already flashed the Xavier NX board with an OS, I ran `dmesg | grep THC` on the board to get the above mentioned output.
I also ran `dmesg | grep Prolific` on the host machine and I’ve shared that output above as well.
I’m actually trying to see the bootloader logs to see if my Trusted Application is working or not. ([as mentioned here](https://forums.developer.nvidia.com/t/how-to-run-the-ca-hwkey-app-and-ta-hwkey-agent-on-target-jetson-agx-xavier/181679) - I want to see where do I get these logs)
---
### Author:  [@WayneWWW](https://forums.developer.nvidia.com/u/WayneWWW)
#### Post date: [September 25, 2021, 10:06am UTC](https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053/4 "2021-09-25T10:06:00Z")
My question is where did you run “dmesg”? Is it also from the uart console?
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### Author:  [@gokulnath136](https://forums.developer.nvidia.com/u/gokulnath136)
#### Post date: [September 25, 2021, 10:18am UTC](https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053/5 "2021-09-25T10:18:03Z")
Never mind, I was able to get the logs. From your link, I realised that my white and green wires were exchanged on the board due to which I wasn’t receiving any data. The guide clearly mentions how do we connect a UART cable to get the required kernel logs.
Thanks a lot for your help!
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### Author:  [@nadeemm](https://forums.developer.nvidia.com/u/nadeemm)
#### Post date: [October 18, 2021, 6:40pm UTC](https://forums.developer.nvidia.com/t/check-bootloader-logs-via-uart/190053/6 "2021-10-18T18:40:34Z")