`arduino-cli` cannot install STMicroelectronics:stm32 on Apple Mac ARM architecture in container

[zfields]

Describe the bug
The arduino-cli can be installed and used, but it cannot install the STMicroelectronics:stm32 BSP

To Reproduce

$ arduino-cli version
arduino-cli  Version: 1.3.1 Commit: 08ff7e2b Date: 2025-08-28T13:51:43Z
$ arduino-cli core install STMicroelectronics:stm32
Error during install: Platform 'STMicroelectronics:stm32': platform is not available for your OS

Expected behavior
Platform is available for aarch64.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: MacOS
• Arduino CLI version: 1.3.1
• STM32 core version: won't attempt to download

Board (please complete the following information):

• Name: Blues Swan

Additional context
It's being used inside a container, so it's the blending of Mac (ARM) + Docker (Linux) that is having the problem.

[fpistm]

Hi @zfields
This request already exists here: stm32duino/Arduino_Tools#103
The core is not linked to arch, only sources. It misses some binaries to be compiled for this arch.
Feel free to contribute.

[zfields]

We'll have something for you shortly.