user81573: I have an ATMega168 that I am programming via my Arduino Uno as ISP. I can burn the bootloader and transfer a hex file just fine, but I can't seem to be able to change the fuse bits. I found a lot of people having similar problems, but most still weren't resolved after many years or can't connect to their chip at all.
A weird thing I notice is that my ATMega is recognized as an 328p all the time. I know they're practically identical, but nothing works when I change settings to an 168, I always have to set it to 328p. Avrdude tells me the signature is wrong, whenever I try it with 168. Might that already be an indicator for something being wrong!? I ordered a 168 and it's printed on the chip, so it should be an actual 168.
Furthermore I noticed that I can only use the Baud rate of 115200, but I read that only 19200 should be correct and when I use that I get no response as well.
This is the command I'm trying to use:
avrdude -Cavrdude.conf -patmega328p -PCOM3 -carduino -b115200 -U efuse:w:0x00:m -U hfuse:w:0xDD:m -U lfuse:w:0xFF:m

And the response I get is:
avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0000
         0x00 != 0xdd
avrdude: verification error; content mismatch

I tried different software and different USB cables, to no avail.
If anyone could provide any direction I can try and look for a solution or mistakes I might have made, I'd be really grateful!

user81573: I got an answer on another forum. I was missing a 10μF capacitor between the Ground and Reset of the Arduino. Not a single documentation, image or video I saw mentioned that. Everything works fine now.

81573: <p>I have an ATMega168 that I am programming via my Arduino Uno as ISP. I can burn the bootloader and transfer a hex file just fine, but I can't seem to be able to change the fuse bits. I found a lot of people having similar problems, but most still weren't resolved after many years or can't connect to their chip at all.</p>
<p>A weird thing I notice is that my ATMega is recognized as an 328p all the time. I know they're practically identical, but nothing works when I change settings to an 168, I always have to set it to 328p. Avrdude tells me the signature is wrong, whenever I try it with 168. Might that already be an indicator for something being wrong!? I ordered a 168 and it's printed on the chip, so it should be an actual 168.</p>
<p>Furthermore I noticed that I can only use the Baud rate of 115200, but I read that only 19200 should be correct and when I use that I get no response as well.</p>
<p>This is the command I'm trying to use:</p>
<pre><code>avrdude -Cavrdude.conf -patmega328p -PCOM3 -carduino -b115200 -U efuse:w:0x00:m -U hfuse:w:0xDD:m -U lfuse:w:0xFF:m
</code></pre>
<p>And the response I get is:</p>
<pre><code>avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0000
         0x00 != 0xdd
avrdude: verification error; content mismatch
</code></pre>
<p>I tried different software and different USB cables, to no avail.</p>
<p>If anyone could provide any direction I can try and look for a solution or mistakes I might have made, I'd be really grateful!</p>
 81573: <p>I got an answer on another forum. I was missing a <strong>10μF capacitor</strong> between the Ground and Reset of the Arduino. Not a single documentation, image or video I saw mentioned that. Everything works fine now.</p>
