This document is about HP EliteBook series laptops up to Ivy Bridge era which use SMSC KBC1126 as embedded controller.
SMSC KBC1126 (and older similar chips like KBC1098) has been used in HP EliteBooks for many generations. BIOS and EC firmware share an SPI flash chip in these laptops, so we need to put firmware blobs for the EC to the coreboot image.
The following document takes EliteBook 2760p as an example.
First, you need to extract the blobs needed by EC firmware using util/kbc1126. You can extract them from your backup firmware image, or firmware update provided by HP with unar as follows:
wget https://ftp.hp.com/pub/softpaq/sp79501-80000/sp79710.exe unar sp79710.exe ${COREBOOT_DIR}/util/kbc1126/kbc1126_ec_dump sp79710/Rompaq/68SOU.BIN mv 68SOU.BIN.fw1 ${COREBOOT_DIR}/2760p-fw1.bin mv 68SOU.BIN.fw2 ${COREBOOT_DIR}/2760p-fw2.bin
When you config coreboot, select:
Chipset ---> [*] Add firmware images for KBC1126 EC (2760p-fw1.bin) KBC1126 firmware #1 path and filename (2760p-fw2.bin) KBC1126 filename #2 path and filename
To port coreboot to an HP laptop with KBC1126, you need to do the following:
EC_HP_KBC1126
SUPERIO_SMSC_LPC47N217
if there is LPC47n217 Super I/O, usually in EliteBook 8000 series, which can be used for debugging via serial portTo get the related values for EC in devicetree.cb, you need to extract the EFI module EcThermalInit from the vendor UEFI firmware with UEFITool. Usually, ec_data_port
, ec_cmd_port
and ec_ctrl_reg
has the following values:
You can use radare2 and the following r2pipe Python script to find these values from the EcThermalInit EFI module:
#!/usr/bin/env python # install radare2 and use `pip3 install --user r2pipe` to install r2pipe import r2pipe import sys if len(sys.argv) < 2: fn = "ecthermalinit.efi" else: fn = sys.argv[1] r2 = r2pipe.open(fn) r2.cmd("aa") entryf = r2.cmdj("pdfj") for insn in entryf["ops"]: if "lea r8" in insn["opcode"]: _callback = insn["ptr"] break r2.cmd("af @ {}".format(_callback)) callbackf_insns = r2.cmdj("pdfj @ {}".format(_callback))["ops"] def find_port(addr): ops = r2.cmdj("pdfj @ {}".format(addr))["ops"] for insn in ops: if "lea r8d" in insn["opcode"]: return insn["ptr"] ctrl_reg_found = False for i in range(0, len(callbackf_insns)): if not ctrl_reg_found and "mov cl" in callbackf_insns[i]["opcode"]: ctrl_reg_found = True ctrl_reg = callbackf_insns[i]["ptr"] print("ec_ctrl_reg = 0x%02x" % ctrl_reg) cmd_port = find_port(callbackf_insns[i+1]["jump"]) data_port = find_port(callbackf_insns[i+3]["jump"]) print("ec_cmd_port = 0x%02x\nec_data_port = 0x%02x" % (cmd_port, data_port)) if "mov bl" in callbackf_insns[i]["opcode"]: ctrl_value = callbackf_insns[i]["ptr"] print("ec_fan_ctrl_value = 0x%02x" % ctrl_value)