What to know about using the lockable Teensy 4.0?

[veroelectric]

We typically use the regular non-locking Teensy 4.0 but with the current shortages we're considering using the lockable 4.0 until the unlocked 4.0s are still in stock. Can we treat the lockable 4.0s the same as the regular 4.0s when it comes to flashing? What does the locking functionality entail?

 

[PaulStoffregen]

Yes, lockable works exactly the same if you don't burn your key and lock it into secure mode, and you don't write to the boot config fuses.

With standard Teensy, you can't write to the boot config fuses even if you try. Those critical bits are permanently protected from changes in standard Teensy. With lockable they're writable. Normal programs wouldn't write to those, so the different is really only if you run very special programs which try to alter those config bits.