Teensy 4.x builds miss framework libraries like SPI and OctoWS2811 #163

Summary

FastLED CI started routing teensy40 and teensy41 through fbuild, and both boards fail because fbuild's Teensy orchestrator does not appear to resolve Teensyduino framework libraries such as SPI and OctoWS2811.

Evidence

FastLED failing job, April 21, 2026:
https://github.com/FastLED/FastLED/actions/runs/24699304962/job/72238880136

The uploaded build summary shows teensy40 all failing with:

fatal error: SPI.h: No such file or directory
#include <SPI.h>

For the Teensy Octo example it also fails with:

fatal error: OctoWS2811.h: No such file or directory
#include <OctoWS2811.h>

The main FastLED build also fails for teensy41 in run 24699304811, job 72238880377; even Blink fails after the Teensy core compiles:

Board: Teensy 4.1 / IMXRT1062 @ 600MHz
Toolchain: arm-none-eabi-gcc 15.2.1
Compiled 85/85 files
fatal error: SPI.h: No such file or directory

Suspected Cause

The fbuild Teensy orchestrator downloads/uses PaulStoffregen/cores and includes the Teensy core directory, project source directories, project include/lib directories, and toolchain include directories, but does not appear to discover or add Teensyduino libraries.

Relevant code:

• crates/fbuild-build/src/teensy/orchestrator.rs
• crates/fbuild-packages/src/library/teensy_core.rs

PaulStoffregen/cores/teensy4 contains Arduino.h, but not SPI.h; those headers live in Teensyduino libraries, so the current include setup is insufficient for FastLED's Teensy 4.x platform headers.

Expected Behavior

fbuild Teensy builds should resolve and compile framework libraries needed by sketches and libraries, including at least:

• SPI
• OctoWS2811

This should behave similarly to PlatformIO's Teensy framework/library resolution.

Reproduction

In FastLED after teensy40 / teensy41 are in ci/compiler/fbuild_boards.py:

./compile --no-interactive --no-parallel --log-failures failures --max-failures 3 teensy40 all
./compile --no-interactive --no-parallel teensy41

The failure is currently reproducible in CI with fbuild 2.1.21.

Notes

FastLED can temporarily fall back to PlatformIO for Teensy 4.x, but the proper fix belongs in fbuild's Teensy library resolution.