Hi @ma_cg
For how to generate and install the toolchain, see Chapter 4.5.12 How to build U-Boot and Kernel in standalone environment in i.MX Linux® User's Guide(https://www.nxp.com/docs/en/user-guide/IMX_LINUX_USERS_GUIDE.pdf)
For how to download and install GNU ARM Toolchain, see Arm GNU Toolchain | GNU Arm Embedded Toolchain Downloads – Arm Developer
Best regards
Harvey