PC $> chmod +x stm32mp1-openstlinux-5.4-dunfell-mp1-20-11-12/sdk/st-image-weston-openstlinux-weston-stm32mp1-x86_64-toolchain-3.1-openstlinux-5.4-dunfell-mp1-20-11-12.sh
PC $> ./stm32mp1-openstlinux-5.4-dunfell-mp1-20-11-12/sdk/st-image-weston-openstlinux-weston-stm32mp1-x86_64-toolchain-3.1-openstlinux-5.4-dunfell-mp1-20-11-12.sh -d $HOME/STM32MPU_workspace/STM32MP15-Ecosystem-v2.1.0/Developer-Package/SDK
If it still doesn't work, please send a screenshot of your steps.