diff --git a/src/mainboard/amd/persimmon/romstage.c b/src/mainboard/amd/persimmon/romstage.c
index da2db64071..749c51b649 100644
--- a/src/mainboard/amd/persimmon/romstage.c
+++ b/src/mainboard/amd/persimmon/romstage.c
@@ -50,6 +50,21 @@ void cache_as_ram_main(unsigned long bist, unsigned long cpu_init_detectedx)
   // all cores: set pstate 0 (1600 MHz) early to save a few ms of boot time
   __writemsr (0xc0010062, 0);
 
+  if (boot_cpu())
+    {
+    u8 reg8;
+    // SB800: program AcpiMmioEn to enable MMIO access to MiscCntrl register
+    outb(0x24, 0xCD6);
+    reg8 = inb(0xCD7);
+    reg8 |= 1;
+    reg8 &= ~(1 << 1);
+    outb(reg8, 0xCD7);
+  
+    // program SB800 MiscCntrl
+    *(volatile u32 *)(0xFED80000+0xE00+0x40) &= ~((1 << 0) | (1 << 2)); /* 48Mhz */
+    *(volatile u32 *)(0xFED80000+0xE00+0x40) |= 1 << 1; /* 48Mhz */
+    }
+
   // early enable of PrefetchEnSPIFromHost
   if (boot_cpu())
     {
@@ -78,17 +93,6 @@ void cache_as_ram_main(unsigned long bist, unsigned long cpu_init_detectedx)
     f81865f_enable_serial(SERIAL_DEV, CONFIG_TTYS0_BASE);
     console_init();
   }
-	//reg8 = pmio_read(0x24);
-  outb(0x24, 0xCD6);
-  reg8 = inb(0xCD7);
-	reg8 |= 1;
-	reg8 &= ~(1 << 1);
-	//pmio_write(0x24, reg8);
-	outb(0x24, 0xCD6);
-	outb(reg8, 0xCD7);
-
-	*(volatile u32 *)(0xFED80000+0xE00+0x40) &= ~((1 << 0) | (1 << 2)); /* 48Mhz */
-	*(volatile u32 *)(0xFED80000+0xE00+0x40) |= 1 << 1; /* 48Mhz */
 
   /* Halt if there was a built in self test failure */
   post_code(0x34);