diff --git a/src/sio/sio_fdc37c669.c b/src/sio/sio_fdc37c669.c
index d49dd9d30..6a8c73563 100644
--- a/src/sio/sio_fdc37c669.c
+++ b/src/sio/sio_fdc37c669.c
@@ -39,7 +39,7 @@ typedef struct fdc37c669_t {
     uint8_t   tries;
     uint8_t   has_ide;
     uint8_t   dma_map[4];
-    uint8_t   irq_map[10];
+    uint8_t   irq_map[16];
     uint8_t   regs[256];
     int       locked;
     int       rw_locked;
diff --git a/src/sio/sio_gm82c803ab.c b/src/sio/sio_gm82c803ab.c
index 8dca4ae6c..8f7749494 100644
--- a/src/sio/sio_gm82c803ab.c
+++ b/src/sio/sio_gm82c803ab.c
@@ -35,7 +35,7 @@ typedef struct gm82c803ab_t {
     uint8_t   type;
     uint8_t   tries;
     uint8_t   has_ide;
-    uint8_t   regs[16];
+    uint8_t   regs[256];
     int       cur_reg;
     int       com3_addr;
     int       com4_addr;
diff --git a/src/sio/sio_gm82c803c.c b/src/sio/sio_gm82c803c.c
index eb54b6661..91c03b369 100644
--- a/src/sio/sio_gm82c803c.c
+++ b/src/sio/sio_gm82c803c.c
@@ -35,7 +35,7 @@ typedef struct gm82c803c_t {
     uint8_t   has_ide;
     uint8_t   dma_map[4];
     uint8_t   irq_map[10];
-    uint8_t   regs[16];
+    uint8_t   regs[256];
     int       cur_reg;
     fdc_t    *fdc;
     serial_t *uart[2];
diff --git a/src/sio/sio_pc87307.c b/src/sio/sio_pc87307.c
index e18d94428..48c2aeb27 100644
--- a/src/sio/sio_pc87307.c
+++ b/src/sio/sio_pc87307.c
@@ -42,7 +42,7 @@ typedef struct pc87307_t {
     uint8_t   baddr;
     uint8_t   pm_idx;
     uint8_t   regs[48];
-    uint8_t   ld_regs[256][208];
+    uint8_t   ld_regs[256][256];
     uint8_t   pcregs[16];
     uint8_t   gpio[2][8];
     uint8_t   pm[8];
diff --git a/src/sio/sio_pc87309.c b/src/sio/sio_pc87309.c
index 9b50f8181..a6e4a5fa3 100644
--- a/src/sio/sio_pc87309.c
+++ b/src/sio/sio_pc87309.c
@@ -42,7 +42,7 @@ typedef struct pc87309_t {
     uint8_t   baddr;
     uint8_t   pm_idx;
     uint8_t   regs[48];
-    uint8_t   ld_regs[256][208];
+    uint8_t   ld_regs[256][256];
     uint8_t   pm[8];
     uint16_t  superio_base;
     uint16_t  pm_base;
diff --git a/src/sio/sio_pc873xx.c b/src/sio/sio_pc873xx.c
index bec747ed2..72c156426 100644
--- a/src/sio/sio_pc873xx.c
+++ b/src/sio/sio_pc873xx.c
@@ -39,7 +39,7 @@ typedef struct pc873xx_t {
     uint8_t   tries;
     uint8_t   has_ide;
     uint8_t   fdc_on;
-    uint8_t   regs[15];
+    uint8_t   regs[256];
     uint16_t  base_addr;
     int       cur_reg;
     int       max_reg;