Briefing
flash_hex passes the HEX path, the MCU name and the wait, soft-reboot and verbose options to teensy_loader_cli, the same as running it with --mcu=TEENSY41 -w -v. Board names such as TEENSY40 and chip IDs such as imxrt1062 are both accepted. soft_reboot puts a Teensy 3.x or 4.x into the HalfKay bootloader without the button. The README's Grok config sets a 180-second timeout per flash, since flashing can wait for the program button.
teensy_loader_cli must be built from PJRC's source and placed on the PATH. Linux needs PJRC's udev rules for access without root. The server is MIT-licensed and only calls the GPL-3.0 CLI binary; it does not ship that source.
Written by the Boards & Bots curator
From the GitHub API
Repository facts
| Repository | johnnyclem/ |
|---|---|
| Stars | 0 |
| License | MIT Permissive |
| Language | Python |
| Last push | 23 Jul 2026 3 mo ago |