diff --git a/src/hwm_lm75.c b/src/hwm_lm75.c
index 8463fbc78..097b62e8e 100644
--- a/src/hwm_lm75.c
+++ b/src/hwm_lm75.c
@@ -128,7 +128,7 @@ lm75_read(lm75_t *dev, uint8_t reg)
     /* The AS99127F hardware monitor uses the addresses of its LM75 devices
        to access some of its proprietary registers. Pass this operation on to
        the main monitor address through an internal SMBus call, if necessary. */
-    if (((reg & 0xf8) != 0x50) && (dev->as99127f_smbus_addr))
+    if ((reg > 0x7) && ((reg & 0xf8) != 0x50) && (dev->as99127f_smbus_addr))
     	ret = smbus_read_byte_cmd(dev->as99127f_smbus_addr, reg);
     else
     	ret = dev->regs[reg & 0x7];
@@ -191,7 +191,7 @@ lm75_write(lm75_t *dev, uint8_t reg, uint8_t val)
     /* The AS99127F hardware monitor uses the addresses of its LM75 devices
        to access some of its proprietary registers. Pass this operation on to
        the main monitor address through an internal SMBus call, if necessary. */
-    if (((reg & 0xf8) != 0x50) && (dev->as99127f_smbus_addr)) {
+    if ((reg > 0x7) && ((reg & 0xf8) != 0x50) && (dev->as99127f_smbus_addr)) {
     	smbus_write_byte_cmd(dev->as99127f_smbus_addr, reg, val);
     	return 1;
     }
diff --git a/src/machine/m_at_slot1.c b/src/machine/m_at_slot1.c
index 1fb640ce4..0c193a678 100644
--- a/src/machine/m_at_slot1.c
+++ b/src/machine/m_at_slot1.c
@@ -229,6 +229,8 @@ machine_at_p3bf_init(const machine_t *model)
     };
     if (model->cpu[cpu_manufacturer].cpus[cpu_effective].cpu_type == CPU_PENTIUM2)
     	machine_hwm.voltages[0] = 2800; /* set higher VCORE (2.8V) for Klamath */
+    else if (model->cpu[cpu_manufacturer].cpus[cpu_effective].cpu_type == CPU_CYRIX3S)
+    	machine_hwm.voltages[0] = 2800; /* P3B-F specific issue: it believes the Cyrix III is a Klamath, and therefore expects a toasty 2.8V */
     hwm_set_values(machine_hwm);
     device_add(&as99127f_device);