Thoughts dereferenced from the scratchpad noise.

Latest posts


Optimizing SPI communication on STM32 MCUs: a comprehensive guide to high-frequency communication

Published at July 28, 2023 · Artur Kowalski ·  22 min read

In this blog post, we delve into the fascinating world of Serial Peripheral Interface (SPI) on STM32 microcontrollers (MCUs). Specifically, we explore how SPI is utilized in TPM chips for communication with PC motherboards. We encounter the challenges of achieving high-frequency SPI communication, especially when operating as a slave, and the specific limitations of STM32L476 MCUs. The article further uncovers the limitations of existing approaches in platforms like Zephyr and STM32 HAL. We then embark on a journey to fix SPI issues, improve DMA performance, and optimize the firmware for high-speed SPI communication. Throughout the blog post, we provide in-depth technical insights and share valuable test results. Join us as we push the boundaries of SPI communication and unlock new possibilities in the world of microcontrollers....

Categories: firmware miscellaneous security

Fobnail Token - example use case

Published at May 19, 2023 · Krystian Hebel ·  11 min read

This phase focused on using Fobnail in a real-life use case, namely using it to access LUKS2 decryption key if and only if the PCR measurements are valid...

Categories: security

Our contribution to coreboot 4.20 release

Published at May 18, 2023 · Piotr Król ·  4 min read

🎉 Celebrating coreboot 4.20 release! 🚀 Kudos to our contributors who have pushed the envelope in firmware security & optimization. Key updates: improved SoC support, TPM security, VT-d DMA protection & more. Check out the blog for all the details....

Categories: firmware

3mdeb Insights: A Look into 3mdeb's Open-Source Contributions

Published at April 27, 2023 · Norbert Kamiński · Piotr Król ·  13 min read

We're thrilled to share our team's summary of open-source contributions from 2021 to the first half of 2023 with you. We've actively worked on enhancing various projects, including coreboot and fwupd. Our involvement has not only boosted the functionality and security of these projects but also equipped us with valuable expertise for our clients. Stay tuned for an insightful blog post diving into our open-source contributions!...

Categories: firmware manufacturing

TrenchBoot Anti Evil Maid for Qubes OS

Published at January 31, 2023 · Michał Żygowski ·  14 min read

Qubes OS Anti Evil Maid (AEM) software heavily depends on the availability of the DRTM technologies to prevent the Evil Maid attacks. However, the project has not evolved much since the beginning of 2018 and froze on the support of TPM 1.2 with Intel TXT in legacy boot mode (BIOS). In the post we show how existing solution can be replaced with TrenchBoot and how one can install it on the Qubes OS. Also the post will also briefly explain how TrenchBoot opens the door for future TPM 2.0 and UEFI support for AEM....

Categories: bootloader firmware hypervisor os-dev security

3mdeb Insights - Winter 2023

Published at January 30, 2023 · Norbert Kamiński ·  5 min read

This blog post will provide an in-depth look at upcoming plans and events for the near future.n the next quarter, we have several exciting events planned for the 3mdeb community. Our events aim to provide a platform for members to connect, share knowledge, and stay informed about the latest developments in the open-source ecosystem....

Categories: firmware miscellaneous

Qubes OS summit 2022 - Summary

Published at October 5, 2022 · Norbert Kamiński ·  10 min read

Three weeks ago 3mdeb with Qubes OS team had organized next edition of the Qubes OS summit. This year summit was a face-to-face event hosted in Berlin, which took place from the 9th to the 11th of September....

Categories: miscellaneous os-dev

Infrastructure for Xen development and debugging

Published at July 4, 2022 · Piotr Król · Norbert Kamiński ·  5 min read

Back in 2018 at OSFC, we've presented AMD IOMMU enabling for PC Engines apuX (GX-412TC) platforms. Our hypervisor of choice was Xen and we used it to verify the PCI pass-through feature. Unfortunately, the booting process was not exactly stable. In this article, you can check how to prepare infrastructure for Xen development and debugging...

Categories: firmware os-dev security

Minimal OS for Fobnail

Published at June 23, 2022 · Tomasz Żyjewski ·  7 min read

The Fobnail Token is an open-source hardware USB device that helps to determine the integrity of the system. The purpose of this blog post is to present the development progress of this project. During this phase, we focused on researching OS for hosting Fobnail Attester...

Categories: security