user88265: I have two UNO boards from a few years ago. They look the same as far as chip placement goes.
I can plug both in and get flashing lights on them, and when I hit the reset (2x the on-off) button, they both make the same LED "noises".  Since the LEDs on the non-detected board flash the same start-up sequence as a board that is detected, I assume both boards are working.
One of them has "UNO" printed on the circuit board and the other has "GCRduino Rev 1.0" printed on the circuit board. (edited according the comments for clarification)
I'm using Linux Mint 21 and Arduino IDE 2.0.3.
On hardinfo (the linux program), both of them are listed in Devices->USB Devices as "QinHeng Electronics CH340 serial converter."
The one that has UNO printed on the board is detected and I can load software onto it. The one that say GCRduino is not detected by the IDE and no new entry shows up in /dev.
The GCRduino is detected for a split second and then disappears again.  check this video: http://100wires.com/arduino.mp4

user88265: I found the problem with dmesg.  When I insert the card and it shows up very briefly, it gets kicked by another device:
[  167.032321] input: BRLTTY 6.4 Linux Screen Driver Keyboard as /devices/virtual/input/input25
[  172.660038] usb 3-3: new full-speed USB device number 9 using xhci_hcd
[  172.809032] usb 3-3: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.62
[  172.809038] usb 3-3: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[  172.809041] usb 3-3: Product: USB2.0-Serial
[  172.810938] ch341 3-3:1.0: ch341-uart converter detected
[  172.811372] usb 3-3: ch341-uart converter now attached to ttyUSB0
[  173.349731] input: BRLTTY 6.4 Linux Screen Driver Keyboard as /devices/virtual/input/input26
[  173.655257] usb 3-3: usbfs: interface 0 claimed by ch341 while 'brltty' sets config #1
[  173.656203] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
[  173.656275] ch341 3-3:1.0: device disconnected

I can see the device on lsusb:
Bus 003 Device 008: ID 1a86:7523 QinHeng Electronics CH340 serial converter
That same device serial number is listed in
grep 1a86 /usr/lib/udev/rules.d/85-brltty.rules
ENV{PRODUCT}=="1a86/7523/*", ENV{BRLTTY_BRAILLE_DRIVER}="bm", GOTO="brltty_usb_run"

So when it connects, it gets kicked off by it being detected as another device.
So I just comment out that line in /usr/lib/udev/rules.d/85-brltty.rules, restart, and the board can now be detected.

88265: <p>I have two UNO boards from a few years ago. They look the same as far as chip placement goes.</p>
<p>I can plug both in and get flashing lights on them, and when I hit the reset (2x the on-off) button, they both make the same LED &quot;noises&quot;.  Since the LEDs on the non-detected board flash the same start-up sequence as a board that is detected, I assume both boards are working.</p>
<p>One of them has &quot;UNO&quot; printed on the circuit board and the other has &quot;GCRduino Rev 1.0&quot; printed on the circuit board. (edited according the comments for clarification)</p>
<p>I'm using Linux Mint 21 and Arduino IDE 2.0.3.</p>
<p>On hardinfo (the linux program), both of them are listed in Devices-&gt;USB Devices as &quot;QinHeng Electronics CH340 serial converter.&quot;</p>
<p>The one that has UNO printed on the board is detected and I can load software onto it. The one that say GCRduino is not detected by the IDE and no new entry shows up in /dev.</p>
<p>The GCRduino is detected for a split second and then disappears again.  check this video: <a href="http://100wires.com/arduino.mp4" rel="nofollow noreferrer">http://100wires.com/arduino.mp4</a></p>
 88265: <p>I found the problem with dmesg.  When I insert the card and it shows up very briefly, it gets kicked by another device:</p>
<pre><code>[  167.032321] input: BRLTTY 6.4 Linux Screen Driver Keyboard as /devices/virtual/input/input25
[  172.660038] usb 3-3: new full-speed USB device number 9 using xhci_hcd
[  172.809032] usb 3-3: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.62
[  172.809038] usb 3-3: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[  172.809041] usb 3-3: Product: USB2.0-Serial
[  172.810938] ch341 3-3:1.0: ch341-uart converter detected
[  172.811372] usb 3-3: ch341-uart converter now attached to ttyUSB0
[  173.349731] input: BRLTTY 6.4 Linux Screen Driver Keyboard as /devices/virtual/input/input26
[  173.655257] usb 3-3: usbfs: interface 0 claimed by ch341 while 'brltty' sets config #1
[  173.656203] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
[  173.656275] ch341 3-3:1.0: device disconnected
</code></pre>
<p>I can see the device on lsusb:</p>
<p>Bus 003 Device 008: ID 1a86:7523 QinHeng Electronics CH340 serial converter</p>
<p>That same device serial number is listed in</p>
<pre><code>grep 1a86 /usr/lib/udev/rules.d/85-brltty.rules
ENV{PRODUCT}==&quot;1a86/7523/*&quot;, ENV{BRLTTY_BRAILLE_DRIVER}=&quot;bm&quot;, GOTO=&quot;brltty_usb_run&quot;
</code></pre>
<p>So when it connects, it gets kicked off by it being detected as another device.</p>
<p>So I just comment out that line in /usr/lib/udev/rules.d/85-brltty.rules, restart, and the board can now be detected.</p>
