Best USB-to-UART Adapter for Hardware Hacking

A USB-to-UART adapter is the single cheapest way into a piece of embedded hardware — clip onto the right three pins on a board and you're often looking at a boot log or a shell, no exploit required. It's the first tool worth buying if hardware hacking is a genuine direction, ahead of anything more specialized.

When to use it

Getting a serial console on a router, IoT device, or any board with an exposed UART header
Reading boot logs to understand what a device actually does on startup, before you've found a way in any other way
Interrupting a bootloader prompt, on devices where that's still possible

What to look for

A genuine chip, not a counterfeit one. FTDI's chips have a well-documented history of counterfeits that Windows drivers were updated to deliberately detect and disable — buying from an authorized retailer instead of the cheapest listing you can find avoids this entirely.
3.3V logic support. Most modern embedded gear runs UART at 3.3V, not 5V — an adapter that only does 5V (or doesn't clearly document which it supports) is a real way to damage a board.
Exposed TX/RX/GND pins on a breakout, not a cable with no easy way to probe or re-wire individual lines.

Adafruit's CP2102N Friend is the one we point people to — a genuine chip from a retailer that doesn't deal in clones, 3.3V-native, and broken out to a header instead of molded into a fixed cable.

Common mistakes

Wiring up VCC because it's right there next to TX/RX/GND — the board is almost always already powered, and backfeeding it from the adapter is a common way to damage hardware that would otherwise have been fine
Assuming the baud rate before checking it — 115200 is common but not universal, and guessing wrong just looks like a dead port rather than a wrong setting
Buying the cheapest adapter listed with no chip name mentioned at all, which is usually how counterfeit-chip adapters get sold

Next step

Once you're reading a serial console, pair this with a logic analyzer if you need to identify an unknown baud rate or protocol before you can talk to it at all.