Picotool 2.1.1 fails to configure on CMake 4.x

[Ferdi265]

When building pico-sdk master with CMake 4.x (without picotool installed on the system), configuring the downloaded picotool 2.1.1 fails due to pico-sdk's version of mbedtls having a too old cmake_minimum_required version.

This issue is worked around on picotool's develop branch since PR#226 by including the mbedtls source files directly, without loading the outdated CMake project. The recent change to pin picotool to a stable release (2.1.1) made this issue resurface.

Steps to reproduce

• clone pico-sdk
• run git submodule update --init
• run cmake -B build && cmake --build build
• build fails (see log)

Versions

• pico-sdk commit 9a4113f
• CMake version 4.0.3-1 (Arch Linux package)

[kilograham]

I imagine this is fixed in the develop branch which uses a newer Mbed TLS

[will-v-pi]

Yes, this is fixed in the picotool and SDK develop branches - the picotool 2.1.1 release and prior will not work with CMake 4.x.x, so you’ll need to downgrade to CMake 3.x.x to use them

I’ll leave open for now for reference, but generally we close issues once they have been fixed on the develop branch

[Ferdi265]

I imagine this is fixed in the develop branch which uses a newer Mbed TLS

yes, develop uses a new enough version of MbedTLS.

[Ferdi265]

Yes, this is fixed in the picotool and SDK develop branches - the picotool 2.1.1 release and prior will not work with CMake 4.x.x, so you’ll need to downgrade to CMake 3.x.x to use them

you can also add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to the picotool CMake invocation in Findpicotool.cmake to use it with newer CMake. I'm currently adding a patched version of Findpicotool.cmake earlier in the CMake module search path in my projects to work around this.

[kilograham]

closing as fixed in develop