Hak4Kidz
The firmware archive calls the device the GrrCON 2026 Hak4Kidz challenge badge, and the writeup names the designer as Hak4Kidz president.
SourceGrrCON 2026 · United States · 2026
GrrCON 2026 15th Anniversary Badge
ATtiny1616 coin-cell admission badge with a hidden serial-console challenge
GrrCON's 15th-anniversary 2026 badge, documented after the September 24-25 conference by an attendee writeup and a published firmware dump, is a coin-cell electronic badge built around a Microchip ATtiny1616. Its artwork shows a green cat with a tentacle mane coiled around a circuit on an amber disc inside a bolted green ring, edged with green LEDs and a single yellow eye LED. A hidden 9600-baud serial console, reached by grounding one pin, asks for a secret code; the answer, rick astley, returns ACCESS GRANTED and a rickroll link. The writeup credits Dave Schwartzberg of Hak4Kidz as designer and challenge author.
EventGrrCON 2026
SeriesGrrCON
LocationDeVos Place, Grand Rapids, Michigan
CountryUnited States
People
Authors & Credits
Dave Schwartzberg
Bryan Smith's writeup credits Dave "Heal" Schwartzberg, Hak4Kidz president and BSides312 organizer, with designing the badge and writing its challenge. No organizer page confirms the credit.
SourceWhy It Mattered
It is the first electronic GrrCON badge in the catalogue tied to the event itself rather than an independent build, and its challenge was designed to need outside tools: the designer warned a week ahead that attendees would need an FTDI adapter and a few wires. The record rests on attendee research, so it keeps the organizer side (count, allocation, credits beyond the designer) open.
Hardware
Attendee research identifies a Microchip ATtiny1616 (tinyAVR 1-series, SOIC-20, 16 KB flash, 256 B EEPROM, signature 0x1E9421) powered by coin cells, green perimeter LEDs plus a yellow eye LED, and one push button. USART0 runs at 9600 8N1 with TX on pin 9 (PB2) and RX on pin 8 (PB3), PC0 on pin 12 is a pulled-up trigger input, and UPDI on pin 16 (PA0) was left enabled and unlocked (SYSCFG0 0xF6). A micro-USB port silkscreened RECHARGE is connected to nothing and is described as a deliberate troll. No schematic, BOM, production count, or organizer photo is published.
Software & Apps
Holding the button at power-on prints Entering Sentinel Watch Mode over the console and runs a watch-mode LED routine; short presses otherwise cycle LED animation modes. Grounding pin 12 prints probe, contact, and handshake accepted, shows ASCII art, and asks for the full name of the person you see; rick astley returns ACCESS GRANTED and a bit.ly GrrCON15b link to a short video before the badge shuts down. The EEPROM starts with a GRRE marker. An attendee dumped the unmodified 16 KB flash and EEPROM over UPDI and published them with SHA-256 checksums and restore notes; no organizer firmware source exists.
Lore
GrrCON 2026 was the Grand Rapids conference's 15th anniversary, held September 24-25, 2026 at DeVos Place. Bryan Smith of Redline Cyber Security, attending for the 13th time, published his badge writeup on September 26, crediting Dave Schwartzberg (Heal), Hak4Kidz president and BSides312 organizer, with the badge and challenge, and published the firmware dump as securekomodo/grrcon-2026-badge-firmware. The official GrrCON homepage still read pre-event on October 1, 2026.
Lifecycle
Add-ons & Upgrades
badge challenge
attendee-documented
Hidden serial-console secret-code challenge
With a 3.3 V USB-serial adapter at 9600 baud, grounding pin 12 starts a probe, contact, handshake accepted sequence and an ASCII-art prompt asking for the full name of the person you see; rick astley returns ACCESS GRANTED and a bit.ly GrrCON15b link to a short video.
Source
hidden firmware mode
attendee-documented
Sentinel Watch Mode
Holding the button while powering on prints Entering Sentinel Watch Mode on the console and switches the LEDs to a separate watch routine instead of the normal animation modes.
SourceOperational history
Issues & Camp Impact
decoy RECHARGE port
low
The micro-USB port marked RECHARGE is connected to nothing, so plugging in USB neither charges nor powers the badge; the attendee firmware archive also warns against powering the badge from a 3.3 V adapter against the coin-cell rail or wiring the badge TX to the adapter TX.
Owners should replace the coin cells rather than expect USB charging and follow the archive's wiring notes when exploring the console.
- Confidence
- attendee hardware inspection
- Status
- design caveat
- Timeframe
- 2026 badge
- Source note
- Redline Cyber Security writeup and securekomodo firmware archive README.
missing rights-cleared image
note
No GrrCON 2026 anniversary badge image is published because neither the attendee writeup nor the firmware archive offers a photo under a reuse licence, and GrrCON has published no official badge image.
The entry stays image-free rather than copying writeup photos.
- Confidence
- local project policy
- Status
- needs licensed original replacement
- Timeframe
- current catalogue build
- Source note
- badge.gallery image policy; Redline Cyber Security writeup and securekomodo firmware archive.
organizer documentation and completion gap
note
All technical detail comes from attendee research published September 26-28, 2026. GrrCON's official homepage still read pre-event on October 1 and names no badge, and no source gives a production count, whether every attendee received one, variants, or the designer's own documentation.
The record treats the badge as a real event artifact without asserting universal allocation, and the edition is not marked completed on official wrap-up evidence.
- Confidence
- attendee sources plus official site
- Status
- attendee-documented; official wrap-up and allocation unpublished
- Timeframe
- post-event as of 2026-10-01
- Source note
- GrrCON official site; Redline Cyber Security writeup; securekomodo firmware archive.
Resources
GrrCON official site
official event page · Official site for the September 24-25, 2026 conference at DeVos Place, Grand Rapids. The October 1, 2026 recheck still found Get Tickets and no recap or badge mention.
Hacking the GrrCON 2026 (15th) Anniversary Badge
attendee badge writeup · Bryan Smith's September 26, 2026 first-hand writeup on the Redline Cyber Security blog covering the artwork, LEDs, the non-functional RECHARGE port, finding the serial pins, the pin-12 trigger, the rick astley answer, and dumping and reflashing the ATtiny1616 over UPDI.
securekomodo/grrcon-2026-badge-firmware
attendee firmware dump · Repository created September 26, 2026 with the unmodified 16 KB flash and 256 B EEPROM read from the badge, SHA-256 checksums, a pinout, console and UPDI wiring, and restore instructions. Organizer-authored firmware, not a source release; no licence is declared.
Sources
Bryan Smith / Redline Cyber Security: Hacking the GrrCON 2026 (15th) Anniversary Badge
Retrieved 2026-10-01 · Secondary first-hand attendee source for the badge's existence at the 15th-anniversary event, the artwork, LED colours, button, coin-cell power, RECHARGE port, the challenge flow and answer, the designer's FTDI warning a week before the con, and the designer credit to Dave Schwartzberg of Hak4Kidz. It does not describe how many badges were made or how they were handed out.
GrrCON: GrrCON Cyber Security and Artificial Intelligence Conference
Retrieved 2026-10-01 · Official event source for the September 24-25, 2026 dates and DeVos Place venue. It does not mention the anniversary badge and still read pre-event on October 1, 2026.
securekomodo / GitHub: GrrCON 2026 (15th) Anniversary Badge Firmware
Retrieved 2026-10-01 · Attendee archive for the ATtiny1616 identification, signature, fuse state, USART0 and UPDI pins, the PC0 trigger, the Sentinel Watch Mode message, and the GRRE EEPROM marker, describing the badge as the GrrCON 2026 Hak4Kidz challenge badge.