diff --git a/arch/risc-v/src/mpfs/mpfs_head.S b/arch/risc-v/src/mpfs/mpfs_head.S
index e6eb6fc8fb3d0..d4e168762f08b 100644
--- a/arch/risc-v/src/mpfs/mpfs_head.S
+++ b/arch/risc-v/src/mpfs/mpfs_head.S
@@ -184,7 +184,8 @@ __start:
 
   /* Set stack pointer to the idle thread stack */
 
-  riscv_set_inital_sp MPFS_IDLESTACK_BASE, SMP_STACK_SIZE, a0
+  addi a1, a0, -1
+  riscv_set_inital_sp MPFS_IDLESTACK_BASE, SMP_STACK_SIZE, a1
 
   /* Jump to __mpfs_start with mhartid in a0 */