Did You Know
Did You Know: A Cheap UGreen USB-C Cable With a Tiny Screen Hid a Chip That Can Play a Rickroll
Inside a €15, 240-watt UGreen charging cable with a voltage display, Aaron Christophel found a Cortex-M0+ microcontroller, hit its SWD pads, and put Rick Astley on the connector.
BERLIN · Noah Park, Did You Know · Nov 6 2026
BERLIN - Did you know that a UGreen USB-C charging cable sold for about 15 euros, with a tiny color screen on the plug that shows volts, amps and watts, also hides a full microcontroller that a hacker reflashed so the cable itself could play a Rickroll? The cable is marked 240 W. Beside the IPS LCD sits a single touch control: a long press turns the display off, and a tap rotates the readout, according to a Notebookcheck hands-on. U.S. list pricing that review cited was about $23 for a 3.3-foot length and $27 for 6.6 feet.
Hardware hacker Aaron Christophel, who posts on YouTube as @atc1441, bought one out of curiosity and tore it open on camera. Getting inside was the hard part. The aluminium shell is not meant to be serviced. After prying at the display cover and cutting into the housing, he reached the board that drives the screen.
Image: Notebookcheck / Andreas Sebayang
The tiny IPS panel connects to the PCB over a flat flex. On that board Christophel found voltage regulators, a MOSFET for the backlight, and an MCU marked EN32LF056. Exposed SWD pads sit under the display. Prodding those pads, he confirmed a Cortex-M0+ core with 64 kB of Flash and 4 kB of SRAM, a finding Hackaday (Maya Posch, Oct. 2, 2026) also reported after watching the video. He first said LF058 on camera, then corrected the marking to 056.
Image: Aaron Christophel via YouTube
With that much Flash on a part that already owns the screen, custom firmware was an obvious next step. He reflashed the MCU so the cable’s own display played frames of Rick Astley’s “Never Gonna Give You Up,” the classic Rickroll, right on the connector. Hackaday called it a party trick once you know how to reach the SWD pads without destroying the assembly.
Image: Aaron Christophel via YouTube
One detail matters more than the joke. The microcontroller is wired only for voltage and current measurement. It is not connected to the USB data lines, so this board cannot act as a keylogger or man-in-the-middle on the cable. That is the opposite of malicious “BadUSB” implants that pretend to be a keyboard. Here the surprise is a metering MCU that happens to be reflashable, not a hidden attack path through D+ and D-.
Image: Aaron Christophel via YouTube
Notebookcheck’s Andreas Sebayang (Oct. 18, 2026) treated the product as a neat charging accessory with a live power readout. Christophel showed what sits behind that readout: a Cortex-M0+ that a patient owner with an SWD probe can turn into a very small music video screen. For about the price of lunch, the cable already ships with the chip, the display, and the pads.
