diff --git a/hw/pxa2xx.c b/hw/pxa2xx.c
index d38b922..e9a507e 100644
--- a/hw/pxa2xx.c
+++ b/hw/pxa2xx.c
@@ -117,6 +117,7 @@ static void pxa2xx_pm_write(void *opaque, target_phys_addr_t addr,
         /* Clear the write-one-to-clear bits... */
         s->pm_regs[addr >> 2] &= ~(value & 0x2a);
         /* ...and set the plain r/w bits */
+        s->pm_regs[addr >> 2] &= ~0x15;
         s->pm_regs[addr >> 2] |= value & 0x15;
         break;