diff --git a/src/mainboard/google/sarien/Kconfig b/src/mainboard/google/sarien/Kconfig
index df5e5b8420..53b92439b0 100644
--- a/src/mainboard/google/sarien/Kconfig
+++ b/src/mainboard/google/sarien/Kconfig
@@ -2,6 +2,7 @@
 config BOARD_GOOGLE_BASEBOARD_SARIEN
 	def_bool n
 	select BOARD_ROMSIZE_KB_32768
+	select DRIVERS_GENERIC_BH720
 	select DRIVERS_I2C_GENERIC
 	select DRIVERS_I2C_HID
 	select DRIVERS_INTEL_ISH if BOARD_GOOGLE_ARCADA
diff --git a/src/mainboard/google/sarien/Makefile.inc b/src/mainboard/google/sarien/Makefile.inc
index eea7f472e6..e7bfc53aa0 100644
--- a/src/mainboard/google/sarien/Makefile.inc
+++ b/src/mainboard/google/sarien/Makefile.inc
@@ -2,6 +2,7 @@
 
 bootblock-y += bootblock.c
 
+ramstage-y += mainboard.c
 ramstage-y += ramstage.c
 ramstage-y += sku.c
 
diff --git a/src/mainboard/google/sarien/mainboard.c b/src/mainboard/google/sarien/mainboard.c
new file mode 100644
index 0000000000..5399e6cd78
--- /dev/null
+++ b/src/mainboard/google/sarien/mainboard.c
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <console/console.h>
+#include <device/mmio.h>
+#include <device/pci.h>
+#include <device/pci_ops.h>
+#include <drivers/generic/bayhub/bh720.h>
+#include <string.h>
+
+void board_bh720(struct device *dev)
+{
+	u32 sdbar;
+	u32 bh720_pcr_data;
+
+	printk(BIOS_DEBUG, "mainboard: %s init\n", __func__);
+	sdbar = pci_read_config32(dev, PCI_BASE_ADDRESS_1);
+
+	/* Enable Memory Access Function */
+	write32((void *)(sdbar + BH720_MEM_ACCESS_EN), 0x40000000);
+	write32((void *)(sdbar + BH720_MEM_RW_DATA), 0x80000000);
+	write32((void *)(sdbar + BH720_MEM_RW_ADR), 0x800000D0);
+
+	/* Set EMMC VCCQ 1.8V PCR 0x308[4] */
+	write32((void *)(sdbar + BH720_MEM_RW_ADR),
+		BH720_MEM_RW_READ | BH720_PCR_EMMC_SETTING);
+	bh720_pcr_data = read32((void *)(sdbar + BH720_MEM_RW_DATA));
+	write32((void *)(sdbar + BH720_MEM_RW_DATA),
+		bh720_pcr_data | BH720_PCR_EMMC_SETTING_1_8V);
+	write32((void *)(sdbar + BH720_MEM_RW_ADR),
+		BH720_MEM_RW_WRITE | BH720_PCR_EMMC_SETTING);
+
+	/* Set Base clock to 200MHz(PCR 0x304[31:16] = 0x2510) */
+	write32((void *)(sdbar + BH720_MEM_RW_ADR),
+		BH720_MEM_RW_READ | BH720_PCR_DrvStrength_PLL);
+	bh720_pcr_data = read32((void *)(sdbar + BH720_MEM_RW_DATA));
+	bh720_pcr_data &= 0x0000FFFF;
+	bh720_pcr_data |= 0x2510 << 16;
+	write32((void *)(sdbar + BH720_MEM_RW_DATA), bh720_pcr_data);
+	write32((void *)(sdbar + BH720_MEM_RW_ADR),
+		BH720_MEM_RW_WRITE | BH720_PCR_DrvStrength_PLL);
+
+	/* Use PLL Base clock PCR 0x3E4[22] = 1 */
+	write32((void *)(sdbar + BH720_MEM_RW_ADR),
+		BH720_MEM_RW_READ | BH720_PCR_CSR);
+	bh720_pcr_data = read32((void *)(sdbar + BH720_MEM_RW_DATA));
+	write32((void *)(sdbar + BH720_MEM_RW_DATA),
+		bh720_pcr_data | BH720_PCR_CSR_EMMC_MODE_SEL);
+	write32((void *)(sdbar + BH720_MEM_RW_ADR),
+		BH720_MEM_RW_WRITE | BH720_PCR_CSR);
+
+	/* Disable Memory Access */
+	write32((void *)(sdbar + BH720_MEM_RW_DATA), 0x80000001);
+	write32((void *)(sdbar + BH720_MEM_RW_ADR), 0x800000D0);
+	write32((void *)(sdbar + BH720_MEM_ACCESS_EN), 0x80000000);
+}
diff --git a/src/mainboard/google/sarien/variants/sarien/devicetree.cb b/src/mainboard/google/sarien/variants/sarien/devicetree.cb
index 09b4240993..1a8e62454b 100644
--- a/src/mainboard/google/sarien/variants/sarien/devicetree.cb
+++ b/src/mainboard/google/sarien/variants/sarien/devicetree.cb
@@ -395,12 +395,20 @@ chip soc/intel/cannonlake
 		device pci 1c.6 off end # PCI Express Port 7
 		device pci 1c.7 on  end # PCI Express Port 8
 		device pci 1d.0 on
+			chip drivers/generic/bayhub
+				register "power_saving" = "1"
+				device pci 00.0 on end
+			end
 			smbios_slot_desc "SlotTypeM2Socket1_SD" "SlotLengthOther" "2230" "SlotDataBusWidth1X"
 		end # PCI Express Port 9
 		device pci 1d.1 on  end # PCI Express Port 10
 		device pci 1d.2 off end # PCI Express Port 11
 		device pci 1d.3 off end # PCI Express Port 12
 		device pci 1d.4 on
+			chip drivers/generic/bayhub
+				register "power_saving" = "1"
+				device pci 00.0 on end
+			end
 			smbios_slot_desc "SlotTypeM2Socket3" "SlotLengthOther" "2280" "SlotDataBusWidth4X"
 		end # PCI Express Port 13 (x4)
 		device pci 1e.0 off end # UART #0