March 2026: Strengthened system reliability and debuggability in Zephyr by delivering targeted bug fixes and API alignment for critical subsystems (mailbox and TISCI clock control). These changes improve fault visibility, prevent regression, and accelerate issue resolution in secure mailbox signaling and clock management, contributing to higher stability in production builds.

This month delivered targeted enhancements across Zephyr and TI firmware to improve reliability, security, and performance. Key features include multi-channel mailbox interrupt support, non-blocking secproxy processing, enhanced device-tree bindings for per-channel interrupts, per-core DT configurations for AM64x R5F, and significant TISCI security hardening with improved error handling.

Month: 2025-12 — Focused work on mailbox reliability in nxp-upstream/zephyr. Delivered a feature to flush the mailbox RX thread on channel enable, ensuring stale messages do not interfere with operation. Implemented secproxy_mailbox_flush_thread() to read and discard pending messages, establishing a clean thread state and preventing errors from prior unclean states. Commit bfeb67b7342edb78c348937a7b72f14f478acf8d documents the change and rationale. Overall impact: more robust mailbox channel initialization, fewer intermittent channel enable failures, and improved determinism in message handling for TI-secproxy integration.

June 2025 monthly summary: Delivered critical reliability and power-management improvements across AmbiqZephyr and the Zephyr-based SDK. Key features and fixes include a mailbox driver ISR userdata bug fix to preserve channel-specific context and prevent cross-channel message misassociation; expanded TISCI test coverage for AM243x/AM2434 in sdk-zephyr, validating TISCI API, PD state management, clock frequency operations, and DMSC interactions; and device-tree based Power Domain configuration plus DMSC system controller support for AM243x/AM2434 to enable PD provisioning for peripherals and system controller nodes. These efforts increased test coverage, reduced risk in power management workflows, and accelerated validation for AM243x/AM2434 deployments.

May 2025 monthly summary for AmbiqMicro/ambiqzephyr: Focused on delivering foundational platform capabilities for secure inter-core operation and expanded hardware support. Key outcomes include a TI TISCI-based system control and secure communication stack and the AM62 SK EVM A53 build target, with improved build/test readiness and clear documentation. These work items enable robust resource management, secure cross-core messaging, and scalable AM62 SK onboarding for future features.