diff --git a/src/devices/sbi/sbi.c b/src/devices/sbi/sbi.c
index 14305bc..4f05820 100644
--- a/src/devices/sbi/sbi.c
+++ b/src/devices/sbi/sbi.c
@@ -13,16 +13,20 @@ void sbi_call(rv32_cpu_t* cpu, uint32_t extension_id, uint32_t func_id)
 				case SBI_FUNCTION_GET_SPEC_VERSION:
 					// Format: [31(reserved,0) 7 bits(major) 24 bits(minor)]
 					// Version 2.0
-					cpu->regs.a0 = 0x2000000;
+					cpu->regs.a0 = 0;
+					cpu->regs.a1 = 0x2000000;
 					break;
 				case SBI_FUNCTION_GET_MVENDOR_ID:
 					cpu->regs.a0 = 0;
+					cpu->regs.a1 = 0;
 					break;
 				case SBI_FUNCTION_GET_MARCH_ID:
 					cpu->regs.a0 = 0;
+					cpu->regs.a1 = 0;
 					break;
 				case SBI_FUNCTION_GET_MIMPL_ID:
 					cpu->regs.a0 = 0;
+					cpu->regs.a1 = 0;
 					break;
 				default:
 					fprintf(stderr, "sbi_call: unknown function id 0x%x for base extension\n", func_id);