#006: Pebble’s Code is Free: Three Former Pebble Engineers Discuss Why It's Important (PART 2/2)
04/15/25 • 73 min
In today’s Coredump Session, the team reunites to unpack the behind-the-scenes lessons from their time building firmware at Pebble. This episode dives into the risks, decisions, and sheer grit behind a near-disastrous OTA update—and the ingenious hack that saved a million smartwatches. It’s a candid look at the intersection of rapid development, firmware stability, and real-world consequences.
Key Takeaways:
- Pebble’s open approach to developer access often came at the cost of security best practices, reflecting early startup trade-offs.
- A critical OTA update bug almost bricked Pebble devices—but the team recovered using a clever BLE-based stack hack.
- Lack of formal security measures at the time (e.g., unsigned firmware) unintentionally enabled recovery from a serious update failure.
- Static analysis and test automation became top priorities following the OTA scare to prevent repeat incidents.
- The story reveals how firmware constraints (like code size and inline functions) can lead to high-stakes bugs.
- Investing in robust release processes—including version-to-version OTA testing—proved vital.
- Real security risks included impersonation on e-commerce platforms and potential ransom via malicious OTA compromise.
- The importance of "hiring your hackers" was humorously noted as a de facto security strategy.
Chapters:
00:00 Episode Teasers & Welcome
01:22 Why Pebble’s Firmware Was Open (and Unsigned)
05:01 The Security Tradeoffs That Enabled Speed
11:00 The OTA Bug That Could Have Bricked Everything
15:26 Hacking Our Way Out with BLE Stack Overflow
17:47 Lessons Learned: Test Automation & Static Analysis
26:30 How Pebble Built a Developer Ecosystem
29:56 CloudPebble, Watchface Generator & Developer Tools
42:55 Backporting Pebble 3.0 to Legacy Hardware
49:02 The Bootloader Rewrite & Other Wild Optimizations
53:31 Simulators, Robot Arms & Debugging in CI56:40 Firmware Signing, Anti-Rollback & Secure Update
1:06:10 Coding in Rust? What We’d Do Differently Today
1:08:28 Where to Start with Open Source Pebble Development
Watch this episode on YouTube
Follow Memfault
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In today’s Coredump Session, the team reunites to unpack the behind-the-scenes lessons from their time building firmware at Pebble. This episode dives into the risks, decisions, and sheer grit behind a near-disastrous OTA update—and the ingenious hack that saved a million smartwatches. It’s a candid look at the intersection of rapid development, firmware stability, and real-world consequences.
Key Takeaways:
- Pebble’s open approach to developer access often came at the cost of security best practices, reflecting early startup trade-offs.
- A critical OTA update bug almost bricked Pebble devices—but the team recovered using a clever BLE-based stack hack.
- Lack of formal security measures at the time (e.g., unsigned firmware) unintentionally enabled recovery from a serious update failure.
- Static analysis and test automation became top priorities following the OTA scare to prevent repeat incidents.
- The story reveals how firmware constraints (like code size and inline functions) can lead to high-stakes bugs.
- Investing in robust release processes—including version-to-version OTA testing—proved vital.
- Real security risks included impersonation on e-commerce platforms and potential ransom via malicious OTA compromise.
- The importance of "hiring your hackers" was humorously noted as a de facto security strategy.
Chapters:
00:00 Episode Teasers & Welcome
01:22 Why Pebble’s Firmware Was Open (and Unsigned)
05:01 The Security Tradeoffs That Enabled Speed
11:00 The OTA Bug That Could Have Bricked Everything
15:26 Hacking Our Way Out with BLE Stack Overflow
17:47 Lessons Learned: Test Automation & Static Analysis
26:30 How Pebble Built a Developer Ecosystem
29:56 CloudPebble, Watchface Generator & Developer Tools
42:55 Backporting Pebble 3.0 to Legacy Hardware
49:02 The Bootloader Rewrite & Other Wild Optimizations
53:31 Simulators, Robot Arms & Debugging in CI56:40 Firmware Signing, Anti-Rollback & Secure Update
1:06:10 Coding in Rust? What We’d Do Differently Today
1:08:28 Where to Start with Open Source Pebble Development
Watch this episode on YouTube
Follow Memfault
Other ways to listen:
Previous Episode
COREDUMP #003: Pebble's Code is Free: Three Former Pebble Engineers Discuss Why It's Important
In this episode of Coredump: Embedded Insights, the Memfault founders—François Baldassari and Chris Coleman—are joined by Brad Murray, former Pebble firmware lead, to explore the now open-sourced Pebble OS. They share war stories from the early days of embedded development, unpack why Pebble’s firmware architecture was years ahead of its time, and highlight the lessons embedded engineers can take from a real, production-grade consumer device.
Topics include:
- Why open-sourcing Pebble OS is a big deal
- The platform strategy behind a single codebase for multiple hardware SKUs
- Custom file systems, app sandboxing, and crash recovery in the real world
- The debugging hacks, performance tricks, and developer tools they wish they had built sooner
This is a rare peek behind the scenes of one of the most iconic embedded products ever shipped.
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