diff --git a/src/chipset/opti5x7.c b/src/chipset/opti5x7.c
index af224437d..d851da766 100644
--- a/src/chipset/opti5x7.c
+++ b/src/chipset/opti5x7.c
@@ -41,6 +41,27 @@ typedef struct
     port_92_t  *port_92;    
 } opti5x7_t;
 
+
+#ifdef ENABLE_OPTI5X7_LOG
+int opti5x7_do_log = ENABLE_OPTI5X7_LOG;
+
+
+static void
+opti5x7_log(const char *fmt, ...)
+{
+    va_list ap;
+
+    if (opti5x7_do_log) {
+	va_start(ap, fmt);
+	pclog_ex(fmt, ap);
+	va_end(ap);
+    }
+}
+#else
+#define opti5x7_log(fmt, ...)
+#endif
+
+
 static void
 opti5x7_recalc(opti5x7_t *dev)
 {
@@ -81,7 +102,7 @@ static void
 opti5x7_write(uint16_t addr, uint8_t val, void *priv)
 {	
     opti5x7_t *dev = (opti5x7_t *) priv;
-    pclog("Write %02x to OPTi 5x7 address %02x\n", val, addr);
+    opti5x7_log("Write %02x to OPTi 5x7 address %02x\n", val, addr);
     
     switch (addr) {
 	case 0x22:
@@ -113,7 +134,7 @@ opti5x7_read(uint16_t addr, void *priv)
 
     switch (addr) {
 	case 0x24:
-			pclog("Read from OPTi 5x7 register %02x\n", dev->idx);
+			opti5x7_log("Read from OPTi 5x7 register %02x\n", dev->idx);
 			ret = dev->regs[dev->idx];
 		break;
     }
diff --git a/src/chipset/stpc.c b/src/chipset/stpc.c
index f0a821f32..6d5177be8 100644
--- a/src/chipset/stpc.c
+++ b/src/chipset/stpc.c
@@ -27,6 +27,8 @@
 #include <86box/rom.h>
 #include <86box/pci.h>
 #include <86box/pic.h>
+#include <86box/timer.h>
+#include <86box/pit.h>
 #include <86box/device.h>
 #include <86box/keyboard.h>
 #include <86box/port_92.h>
@@ -631,6 +633,9 @@ stpc_reg_write(uint16_t addr, uint8_t val, void *priv)
 
 		case 0x56: case 0x57:
 			/* ELCR goes here */
+			elcr_write(dev->reg_offset, val, NULL);
+			if (dev->reg_offset == 0x57)
+				refresh_at_enable = val & 0x01;
 			break;
 	}
 
@@ -649,7 +654,11 @@ stpc_reg_read(uint16_t addr, void *priv)
 	ret = dev->reg_offset;
     else if (dev->reg_offset >= 0xc0)
     	return 0xff; /* Cyrix CPU registers: let the CPU code handle those */
-    else
+    else if ((dev->reg_offset == 0x56) || (dev->reg_offset == 0x57)) {
+	ret = elcr_read(dev->reg_offset, NULL);
+	if (dev->reg_offset == 0x57)
+		ret |= (dev->regs[dev->reg_offset] & 0x01);
+    } else
 	ret = dev->regs[dev->reg_offset];
 
     stpc_log("STPC: reg_read(%04X) = %02X\n", addr, ret);
@@ -837,6 +846,9 @@ stpc_init(const device_t *info)
 
     device_add(&port_92_pci_device);
 
+    pci_elcr_io_disable();
+    refresh_at_enable = 0;
+
     return dev;
 }
 
diff --git a/src/device/keyboard_at.c b/src/device/keyboard_at.c
index ee5b0f496..8415538c9 100644
--- a/src/device/keyboard_at.c
+++ b/src/device/keyboard_at.c
@@ -2207,6 +2207,7 @@ kbd_read(uint16_t port, void *priv)
 {
     atkbd_t *dev = (atkbd_t *)priv;
     uint8_t ret = 0xff;
+    static int flip_flop = 0;
 
     if ((dev->flags & KBC_TYPE_MASK) >= KBC_TYPE_PS2_NOREF)
 	sub_cycles(ISA_CYCLES(8));
@@ -2244,11 +2245,14 @@ kbd_read(uint16_t port, void *priv)
                         else
                                 ret &= ~0x04;
                 }
+#ifdef USE_DYNAREC
+		flip_flop = (flip_flop + 1) & 3;
+		if (cpu_use_dynarec && (flip_flop == 3))
+			update_tsc();
+#endif
 		break;
 
 	case 0x64:
-		// ret = (dev->status & 0xFB) | (keyboard_mode & CCB_SYSTEM);
-		// ret |= STAT_UNLOCKED;
 		ret = (dev->status & 0xFB);
 		if (dev->mem[0] & STAT_SYSFLAG)
 			ret |= STAT_SYSFLAG;
diff --git a/src/floppy/fdc.c b/src/floppy/fdc.c
index c49ba984d..47784982a 100644
--- a/src/floppy/fdc.c
+++ b/src/floppy/fdc.c
@@ -1350,10 +1350,6 @@ fdc_read(uint16_t addr, void *priv)
 		break;
 	case 4: /*Status*/
 		ret = fdc->stat;
-#ifdef USE_DYNAREC
-		if (cpu_use_dynarec)
-			update_tsc();
-#endif
 		break;
 	case 5: /*Data*/
 		if ((fdc->stat & 0xf0) == 0xf0) {
@@ -1891,7 +1887,7 @@ fdc_data(fdc_t *fdc, uint8_t data)
 void
 fdc_finishread(fdc_t *fdc)
 {
-        fdc->inread = 0;
+    fdc->inread = 0;
 }
 
 
diff --git a/src/include/86box/pci.h b/src/include/86box/pci.h
index 7fb118195..830324c1a 100644
--- a/src/include/86box/pci.h
+++ b/src/include/86box/pci.h
@@ -103,6 +103,9 @@ extern uint8_t	trc_read(uint16_t port, void *priv);
 extern void	trc_write(uint16_t port, uint8_t val, void *priv);
 
 extern void	pci_elcr_set_enabled(int enabled);
+extern void	pci_elcr_io_disable(void);
+extern void	elcr_write(uint16_t port, uint8_t val, void *priv);
+extern uint8_t	elcr_read(uint16_t port, void *priv);
 
 
 #endif	/*EMU_PCI_H*/
diff --git a/src/include/86box/pit.h b/src/include/86box/pit.h
index 4684c9632..366be2ad6 100644
--- a/src/include/86box/pit.h
+++ b/src/include/86box/pit.h
@@ -59,6 +59,8 @@ extern uint64_t	PITCONST, ISACONST,
 		VGACONST2,
 		RTCCONST, ACPICONST;
 
+extern int	refresh_at_enable;
+
 
 /* Gets a counter's count. */
 extern uint16_t	pit_ctr_get_count(ctr_t *ctr);
diff --git a/src/io.c b/src/io.c
index f78dc268e..b9dfcf370 100644
--- a/src/io.c
+++ b/src/io.c
@@ -283,18 +283,19 @@ uint8_t
 inb(uint16_t port)
 {
     uint8_t ret = 0xff;
-    io_t *p;
+    io_t *p, *q;
     int found = 0;
     int qfound = 0;
 
     p = io[port];
     while(p) {
+	q = p->next;
 	if (p->inb) {
 		ret &= p->inb(port, p->priv);
 		found |= 1;
 		qfound++;
 	}
-	p = p->next;
+	p = q;
     }
 
     if (port & 0x80)
@@ -316,18 +317,19 @@ inb(uint16_t port)
 void
 outb(uint16_t port, uint8_t val)
 {
-    io_t *p;
+    io_t *p, *q;
     int found = 0;
     int qfound = 0;
 
     p = io[port];
     while(p) {
+	q = p->next;
 	if (p->outb) {
 		p->outb(port, val, p->priv);
 		found |= 1;
 		qfound++;
 	}
-	p = p->next;
+	p = q;
     }
 	
     if (!found) {
@@ -347,7 +349,7 @@ outb(uint16_t port, uint8_t val)
 uint16_t
 inw(uint16_t port)
 {
-    io_t *p;
+    io_t *p, *q;
     uint16_t ret = 0xffff;
     int found = 0;
     int qfound = 0;
@@ -356,12 +358,13 @@ inw(uint16_t port)
 
     p = io[port];
     while(p) {
+	q = p->next;
 	if (p->inw) {
 		ret &= p->inw(port, p->priv);
 		found |= 2;
 		qfound++;
 	}
-	p = p->next;
+	p = q;
     }
 
     ret8[0] = ret & 0xff;
@@ -369,12 +372,13 @@ inw(uint16_t port)
     for (i = 0; i < 2; i++) {
 	p = io[(port + i) & 0xffff];
 	while(p) {
+		q = p->next;
 		if (p->inb && !p->inw) {
 			ret8[i] &= p->inb(port + i, p->priv);
 			found |= 1;
 			qfound++;
 		}
-		p = p->next;
+		p = q;
 	}
     }
     ret = (ret8[1] << 8) | ret8[0];
@@ -398,30 +402,32 @@ inw(uint16_t port)
 void
 outw(uint16_t port, uint16_t val)
 {
-    io_t *p;
+    io_t *p, *q;
     int found = 0;
     int qfound = 0;
     int i = 0;
 
     p = io[port];
     while(p) {
+	q = p->next;
 	if (p->outw) {
 		p->outw(port, val, p->priv);
 		found |= 2;
 		qfound++;
 	}
-	p = p->next;
+	p = q;
     }
 
     for (i = 0; i < 2; i++) {
 	p = io[(port + i) & 0xffff];
 	while(p) {
+		q = p->next;
 		if (p->outb && !p->outw) {
 			p->outb(port + i, val >> (i << 3), p->priv);
 			found |= 1;
 			qfound++;
 		}
-		p = p->next;
+		p = q;
 	}
     }
 
@@ -442,7 +448,7 @@ outw(uint16_t port, uint16_t val)
 uint32_t
 inl(uint16_t port)
 {
-    io_t *p;
+    io_t *p, *q;
     uint32_t ret = 0xffffffff;
     uint16_t ret16[2];
     uint8_t ret8[4];
@@ -452,12 +458,13 @@ inl(uint16_t port)
 
     p = io[port];
     while(p) {
+	q = p->next;
 	if (p->inl) {
 		ret &= p->inl(port, p->priv);
 		found |= 4;
 		qfound++;
 	}
-	p = p->next;
+	p = q;
     }
 
     ret16[0] = ret & 0xffff;
@@ -465,12 +472,13 @@ inl(uint16_t port)
     for (i = 0; i < 4; i += 2) {
 	p = io[(port + i) & 0xffff];
 	while(p) {
+		q = p->next;
 		if (p->inw && !p->inl) {
 			ret16[i >> 1] &= p->inw(port + i, p->priv);
 			found |= 2;
 			qfound++;
 		}
-		p = p->next;
+		p = q;
 	}
     }
     ret = (ret16[1] << 16) | ret16[0];
@@ -482,12 +490,13 @@ inl(uint16_t port)
     for (i = 0; i < 4; i++) {
 	p = io[(port + i) & 0xffff];
 	while(p) {
+		q = p->next;
 		if (p->inb && !p->inw && !p->inl) {
 			ret8[i] &= p->inb(port + i, p->priv);
 			found |= 1;
 			qfound++;
 		}
-		p = p->next;
+		p = q;
 	}
     }
     ret = (ret8[3] << 24) | (ret8[2] << 16) | (ret8[1] << 8) | ret8[0];
@@ -511,7 +520,7 @@ inl(uint16_t port)
 void
 outl(uint16_t port, uint32_t val)
 {
-    io_t *p;
+    io_t *p, *q;
     int found = 0;
     int qfound = 0;
     int i = 0;
@@ -519,36 +528,39 @@ outl(uint16_t port, uint32_t val)
     p = io[port];
     if (p) {
 	while(p) {
+		q = p->next;
 		if (p->outl) {
 			p->outl(port, val, p->priv);
 			found |= 4;
 			qfound++;
 		}
-		p = p->next;
+		p = q;
 	}
     }
 
     for (i = 0; i < 4; i += 2) {
 	p = io[(port + i) & 0xffff];
 	while(p) {
+		q = p->next;
 		if (p->outw && !p->outl) {
 			p->outw(port + i, val >> (i << 3), p->priv);
 			found |= 2;
 			qfound++;
 		}
-		p = p->next;
+		p = q;
 	}
     }
 
     for (i = 0; i < 4; i++) {
 	p = io[(port + i) & 0xffff];
 	while(p) {
+		q = p->next;
 		if (p->outb && !p->outw && !p->outl) {
 			p->outb(port + i, val >> (i << 3), p->priv);
 			found |= 1;
 			qfound++;
 		}
-		p = p->next;
+		p = q;
 	}
     }
 
diff --git a/src/machine/m_at.c b/src/machine/m_at.c
index 7adc98ecd..9ee653a32 100644
--- a/src/machine/m_at.c
+++ b/src/machine/m_at.c
@@ -64,6 +64,7 @@ machine_at_common_init_ex(const machine_t *model, int type)
 {
     machine_common_init(model);
 
+    refresh_at_enable = 1;
     pit_ctr_set_out_func(&pit->counters[1], pit_refresh_timer_at);
     pic2_init();
     dma16_init();
diff --git a/src/machine/m_ps1.c b/src/machine/m_ps1.c
index 651ef1d25..f308d969a 100644
--- a/src/machine/m_ps1.c
+++ b/src/machine/m_ps1.c
@@ -506,6 +506,7 @@ ps1_common_init(const machine_t *model)
 
     mem_remap_top(384);
 
+    refresh_at_enable = 1;
     pit_ctr_set_out_func(&pit->counters[1], pit_refresh_timer_at);
 
     dma16_init();
diff --git a/src/machine/m_ps2_isa.c b/src/machine/m_ps2_isa.c
index 9300d05d4..226a3eda4 100644
--- a/src/machine/m_ps2_isa.c
+++ b/src/machine/m_ps2_isa.c
@@ -178,6 +178,7 @@ machine_ps2_m30_286_init(const machine_t *model)
 
 	device_add(&fdc_at_ps1_device);
 
+	refresh_at_enable = 1;
         pit_ctr_set_out_func(&pit->counters[1], pit_refresh_timer_at);
         dma16_init();
 	device_add(&keyboard_ps2_ps2_device);
diff --git a/src/pci.c b/src/pci.c
index ace9e14e5..336cd8d2f 100644
--- a/src/pci.c
+++ b/src/pci.c
@@ -189,7 +189,7 @@ pci_read(uint16_t port, void *priv)
 }
 
 
-static void
+void
 elcr_write(uint16_t port, uint8_t val, void *priv)
 {
     pci_log("ELCR%i: WRITE %02X\n", port & 1, val);
@@ -214,7 +214,7 @@ elcr_write(uint16_t port, uint8_t val, void *priv)
 }
 
 
-static uint8_t
+uint8_t
 elcr_read(uint16_t port, void *priv)
 {
     pci_log("ELCR%i: READ %02X\n", port & 1, elcr[port & 1]);
@@ -641,6 +641,14 @@ pci_elcr_set_enabled(int enabled)
 }
 
 
+void
+pci_elcr_io_disable(void)
+{
+    io_removehandler(0x04d0, 0x0002,
+		     elcr_read,NULL,NULL, elcr_write,NULL,NULL, NULL);
+}
+
+
 static void
 pci_reset_regs(void)
 {
diff --git a/src/pit.c b/src/pit.c
index fec976d79..9e140650d 100644
--- a/src/pit.c
+++ b/src/pit.c
@@ -53,7 +53,8 @@ uint64_t	PITCONST, ISACONST,
 		VGACONST1, VGACONST2,
 		RTCCONST, ACPICONST;
 
-int		io_delay = 5;
+int		refresh_at_enable = 1,
+		io_delay = 5;
 
 
 int64_t		firsttime = 1;
@@ -743,7 +744,7 @@ pit_refresh_timer_xt(int new_out, int old_out)
 void
 pit_refresh_timer_at(int new_out, int old_out)
 {
-    if (new_out && !old_out)
+    if (refresh_at_enable && new_out && !old_out)
 	ppi.pb ^= 0x10;
 }
 
diff --git a/src/sio/sio_pc87307.c b/src/sio/sio_pc87307.c
index 0921c4677..0a1578c76 100644
--- a/src/sio/sio_pc87307.c
+++ b/src/sio/sio_pc87307.c
@@ -413,11 +413,11 @@ pc87307_read(uint16_t port, void *priv)
 	ret = dev->cur_reg;
     else {
 	if (dev->cur_reg >= 0x30)
-		ret = dev->regs[dev->cur_reg];
+		ret = dev->ld_regs[dev->regs[0x07]][dev->cur_reg - 0x30];
 	else if (dev->cur_reg == 0x24)
 		ret = dev->pcregs[dev->regs[0x23]];
 	else
-		ret = dev->ld_regs[dev->regs[0x07]][dev->cur_reg - 0x30];
+		ret = dev->regs[dev->cur_reg];
     }
 
     return ret;
diff --git a/src/sio/sio_pc87309.c b/src/sio/sio_pc87309.c
index f60d02374..0b55b9655 100644
--- a/src/sio/sio_pc87309.c
+++ b/src/sio/sio_pc87309.c
@@ -337,9 +337,9 @@ pc87309_read(uint16_t port, void *priv)
     if (index)
 	ret = dev->cur_reg & 0x1f;
     else {
-	if (dev->cur_reg == 8)
-		ret = 0x70;
-	else if (dev->cur_reg < 28)
+	if (dev->cur_reg >= 0x30)
+		ret = dev->ld_regs[dev->regs[0x07]][dev->cur_reg - 0x30];
+	else
 		ret = dev->regs[dev->cur_reg];
     }