Soldering headers screwed up Trinket? Last week I purchased a couple of Trinkets from Adafruit (5v micro-USB). The first thing I did was solder the headers to one of them. I did the whole setup process w/ the Arduino IDE and didn't have any issues, until I actually tried uploading the "Blink" example.

When I plug in the Trinket, I get the pulsing red light, but when I try to upload during that, I get:

avrdude: error: usbtiny_send: Input/output error (expected 64, got -5)
avrdude: verification error, first mismatch at byte 0x0004
         0x1d != 0x36
avrdude: verification error; content mismatch

avrdude: error: usbtiny_transmit: Input/output error


Then, if I press the reset button, I can't get it to "pulse" again. The red light just dimly turns on and stays constant.

I tested the other Trinket I ordered (that has not been soldered yet) and it works perfectly fine.

So, did I somehow screw up something when soldering the headers? Or do I have a faulty Trinket?

For reference, here's the trinket in question...
There are what appear to be burn or melt marks on the 5 pin component labeled QTSO and on the diode near the USB pin. That could be a sign of damage due to soldering, reverse polarity, or excessive current draw through the voltage regulator (a short circuit).

Based on the fact that the light stays on solid when the reset button is pressed,  it sounds like it could also a different issue. First, turn on verbose output in the arduino IDE and post the full output when you try to upload. 

Next, try disconnecting everything except the USB cable while uploading the program. If that does not fix it, it is most likely that the bootloader is corrupted. This has happened to me on multiple occasions for no apparent reason and it is pretty easy to fix. 

If repairing the bootloader does not fix this, it is most likely that one or both of the components mentioned above are damaged.