The Laird Connectivity platform board BL5340 DVK no longer compiles in the main branch of TF-M after the split build feature was merged. The BL5340 DVK is a module that contains the nRF5340 SoC, because of this the platform is re-using the Nordic platform support files. This cross-reference is causing us, the maintainers of Nordic a lot of problems as making changes to the Nordic platform code can break the Laird Connectivity platform. We don't have this board either to run any tests and confirm any changes. Laird Connectivity has not contributed to the platform support for more than a year.
Nordics strategy for maintaining support for TF-M is to have the base DK supported in TF-M for testing purposes, and then provide support for all other boards in our SDK through our board support configuration system. Removing the platform from TF-M will still mean that the BL5340 DVK board is supported in the nRF Connect SDK.
To support the board in the Zephyr Project the following PR is needed: https://github.com/zephyrproject-rtos/zephyr/pull/65823
Joakim Andersson Nordic Semiconductor