Yes, FreeRTOS sets a mask register that controls what interrupt priorities can trigger to configMAX_SYSCALL_INTERRUPT_PRIORITY, which means interrupts of that priority or greater-value lower-priority are blocked, and lesser-value higher-priority can still happen. The ordering of interrupt priorities is the reverse of the value, so higher priority is lesser value. (and I try to always use higher or lower, never greater or lesser (as well as the mathematical symbols) as those tend to refer to the NUMBERS (as in priority value), not the priority order of the interrupts