v19.5.0

This is a working draft for the up-coming 19.5.0 release.

We are pleased to announce the release of TT Zephyr Platforms firmware version 19.5.0 🥳🎉.

Major enhancements with this release include:

Wormhole Changes

Stability Improvements

Update ERISC FW to 7.5.0, change list from 7.2.0:
- 7.5.0
  - Adjust the resend chip info packet time to resolve the link training failures with ANLT ports
  - Minimize static training retries to compensate for longer delays in the training sequence
  - Adjust DFE settings for weak lanes only to improve the link stability
- 7.4.0
  - Code clean-up and documentation
  - Use register defines and convert arrays into data structures
- 7.3.0
  - Fix retrain hangs with Active Cables
  - Adjust DFE value to improve BER on WH UBB QSFP ports
  - Link quality improvements to non-retimer long trace on WH UBB
  - Updated retraining logic to set train_status to LINK_TRAIN_TRAINING when entering into retraining
  - Remove link_training_fw_phony debug feature from eth_init to free up more space

Blackhole Changes

p150 Tensix Core Count

Beginning January 2026, all Blackhole p150 accelerator cards (p150a, p150b) will ship with 120 Tensix cores instead of 140. To present a unified interface to metal and other system software, firmware v19.5.0 and later will change the core count on all existing cards to 120. Typical workloads show a non-material (~1–2%) performance difference. You may observe a change in grid size in metal, which may require updates to applications that depend on grid layout.

Stability Improvements

Fixed boardcfg loading error handling in recovery image

Power Management

Galaxy TDP limit reduced from 170 W to 130 W to stay within system power limits
Disabled PHY powerdown for MRISC on Galaxy systems to address DRAM funtest regression

Telemetry & Monitoring

Added telemetry entries for enabled AICLK min/max arbiters (TAG_ENABLED_MIN_ARB and TAG_ENABLED_MAX_ARB)
Added telemetry for effective AICLK min/max arbiter values (TAG_AICLK_ARB_MIN and TAG_AICLK_ARB_MAX)
Added Doxygen documentation for aiclk_arb_max and aiclk_arb_min enumerations
PVT sensor message fixes
- Revert backward-incompatible message interface changes to READ_{TS,PD,VM} introduced in v19.1.0
- Fixed conversion truncation issue in voltage monitoring messages
- Improved error checking in PVT functions
Added tracing for AICLK updates (disabled by default)

Drivers

Added interrupt support to ARC DMA driver and enabled it by default
Added “is alive” check to PVT sensor drivers

Tooling

Add support for newer P300 boards to blackhole recovery script
Properly support flash read across multiple blocks with pyocd
tt-tracing improvements
- Added -b command-line argument to select BAR (bar0 or bar4)
- Improved tracing performance when running in parallel with tt-burnin
- Fixed to send enable tracing command only once (not on every loop iteration)
- Updated documentation with coding examples for custom tracing events
- Fixed babeltrace2 version to 2.0.4 for compatibility

Build System & Dependencies

Migrated from patch-based workflow to Zephyr fork
Removed all usages of west patch treewide
Fixed git describe to use correct module directory (enables correct version tags for applications built in different repositories)

Grendel Changes

Initial support added for the Grendel SMC platform
- 4-core Berkeley Rocketcore with peripheral complement for external device interfacing
Initial devicetree definition
Virtual console driver for simulation debugging via printf
Basic build workflow for CI validation

Migration guide

An overview of required and recommended changes to make when migrating from the previous v19.4.0 release can be found in 19.5 Migration Guide.

Full ChangeLog

The full ChangeLog from the previous v19.4.0 release can be found at the link below.

https://github.com/tenstorrent/tt-zephyr-platforms/compare/v19.4.0…v19.5.0