diff --git a/src/chipset/umc_8886.c b/src/chipset/umc_8886.c
index c612e1974..ded9c7e56 100644
--- a/src/chipset/umc_8886.c
+++ b/src/chipset/umc_8886.c
@@ -202,7 +202,7 @@ umc_8886_write(int func, int addr, uint8_t val, void *priv)
                     case 0x56:
                         dev->pci_conf_sb[func][addr] = val;
 
-                        switch (val & 2) {
+                        switch (val & 3) {
                             case 0:
                                 cpu_set_isa_pci_div(3);
                                 break;