December 7, 2025
Finger on the pulse of drama
Patching Pulse Oximeter Firmware
Hacker bricks “German” oximeter; comments roast font and cheer $3 clones
TLDR: A hacker dumped the Beurer PO 80’s firmware by exploiting a chip flaw and even bricking the device, then shared tools to read data. Commenters mocked the “German engineering” claim, roasted the B-vs-8 font fiasco, and celebrated that similar oximeters cost under $3, fueling budget hack fever.
A tinkerer cracked open the Beurer PO 80 pulse oximeter—the fingertip gadget that reads your heart rate and blood oxygen—and used a known chip flaw to dump its firmware after literally bricking the device. They sniffed the USB chatter, wrote a Python tool to pull live data, and posted it all on GitHub. That’s the plot twist. The real show? The comments went full popcorn mode.
First, the “German engineering” label got side‑eyed when the bundled PC app looked suspiciously… not German. Then came the chaos over a chip mix‑up: one commenter ranted that the letter B looks like an 8 on the part number, dubbing it font crimes. Another stoked the fire by pointing out you can grab lookalike oximeters on AliExpress for under $3, turning this into the penny‑pincher hacker Olympics. People joked about why the software has a “patient name” field—what are we, naming our fingers? And yes, there were spicy debates: is bricking a device “worth it” for science, or just tech cruelty? The vibe: DIY medical gadget hacking is fun, cheap, and maybe a little chaotic, with the crowd split between roasting marketing myths and gleefully planning $3 weekend mod projects.
Key Points
- •The Beurer PO 80 pulse oximeter communicates with PCs via a custom USB HID protocol and supports the SpO2 Assistant software.
- •Dynamic protocol sniffing, rather than static decompilation, enabled partial reverse engineering of device communications.
- •A Python tool was developed to initialize the device and retrieve pulse and SpO2 data; code is available on GitHub.
- •Teardown identified a GD32F350RBT6 (Arm Cortex-M4) microcontroller, 240×240 display, serial flash, accelerometer, and an unpopulated Bluetooth footprint.
- •A known GD32 hardware vulnerability enabled bypassing low-level flash readout protection to dump firmware, at the cost of bricking the chip.