Build the Coreboot ROM Image (ThinkPad T400) ============================================ Copyright (C) 2018, 2019, 2021, 2022 Kai Mertens Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". TODO: This file lists essential steps for reference only and should be thoroughly reviewed. Please use the toolchain scripts instead. See `../doc/toolchain.md`. Prepare ------- See Coreboot Build How-To: Basically: $ git clone https://review.coreboot.org/coreboot $ cd coreboot $ git checkout 4.8.1 $ git submodule update --init --checkout $ make crossgcc-i386 Coreboot Configuration ---------------------- $ make menuconfig Use default values, but additionally select/deselect as specified: * Mainboard - Mainboard vendor (Lenovo) ---> - Mainboard model (ThinkPad T400) ---> - ROM chip size (8192 KB (8 MB)) ---> NOTE: Select the appropriate ROM chip size of your X200 model (4, 8, 16MB) and substract 0x3000 to get the correct size of region BIOS, or like it is called here: “Size of CBFS filesystem in ROM”. - (0x7fd000) Size of CBFS filesystem in ROM NOTE: The original size of flash region 1 (BIOS) is 0x200000, but we are going to use a libreboot-modified descriptor which deletes region 2 (IME-Firmware) and increases region 1. * General Setup - [*] Use CMOS for configuration values * Chipset - Include CPU microcode in CBFS (Generate from tree) ---> NOTE: Include CPU microcode in order to avoid occasional freezes which otherwise might occur with VMX and video usage. Note that we are not d'accord with any proprietary license status of that blob or its sources, but machines that occasionally hang without warning is not an option, either. * Devices - Graphics initialization (Use native graphics init) ---> - Display ---> + Framebuffer mode (Linear "high-resolution" framebuffer) ---> * Console - [ ] Serial port console output Keep serial port clean upon boot. It might otherwise interfere with attached devices, the Zerocat Chipflasher for instance. * Payload - Add a payload (An ELF executable payload) ---> - `"(payload.elf)"` Payload path and filename NOTE: File `payload.elf` should match your previously built executable GRUB payload file for platform i386-coreboot. See [GRUB How-To][]. - Secondary Payloads ---> + Select: Load coreinfo as a secondary payload + Select: Load nvramcui as a secondary payload NOTE: The `.config` file may contain your paths which you probably don't want to share with others. Compile ------- When you have exit the menuconfig tool, type: $ make This will provide the `coreboot.rom` in folder `build/`. Add Custom Files ---------------- ### Add Zerocat’s GRUB Configuration File Use coreboot’s `cbfstool` to add the custom configuration file as `etc/zerocat.cfg`: $ build/cbfstool build/coreboot.rom \ add -t raw -n etc/zerocat.cfg -f $ build/cbfstool build/coreboot.rom \ print See [grub@2.02_zerocat.cfg][] for reference. Before using it, please edit the file and adjust your keyboard layout which is currently pre-set via `keymap`. ### Secondary Payloads #### NVRAMCUI and Coreinfo Secondary payloads `nvramcui` and `coreinfo` should be accompanied with an informative message about occasional freezes, what can be achieved with GRUB, but not with SeaBIOS. Therefor, let’s move them out of the SeaBIOS `img/` search path: $ for i in coreinfo nvramcui; do \ build/cbfstool build/coreboot.rom \ extract -m x86 -n img/$i -f $i.extracted && \ build/cbfstool build/coreboot.rom \ remove -n img/$i && \ build/cbfstool build/coreboot.rom \ add-payload -c lzma -n $i -f $i.extracted && \ rm $i.extracted; \ done; NOTE: When invoking `coreinfo` fromout the GRUB Boot Menu, please get prepared for occasional freezes due to CPU exceptions and faults. See [Coreinfo CPU Exceptions][]. NOTE: When invoking `nvramcui` fromout the GRUB Boot Menu, switch your RF Kill Switch off! Active bluetooth devices might freeze the application. NOTE: Hmm..., and secondary payloads `nvramcui` and `coreinfo` seem to freeze in case a fingerprint sensor is part of the system, so please unplug that sensor. ### Add SeaBIOS Payload [Zerocat’s GRUB Configuration File][grub@2.02_zerocat.cfg] already comes with a menu entry to chainload the SeaBIOS payload. Add files to the `coreboot.rom` as required: $ build/cbfstool build/coreboot.rom \ add -t raw -n config-seabios -f $ build/cbfstool build/coreboot.rom \ add -t raw -n vgaroms/vgabios.bin -f $ build/cbfstool build/coreboot.rom \ add-payload -n seabios.elf -f $ build/cbfstool build/coreboot.rom \ print Please read section “Adding SeaBIOS Payload” of the [GRUB How-To][] for more information. ### Add Background Image [Zerocat’s GRUB Configuration File][grub@2.02_zerocat.cfg] has already been prepared to make use of a background image, if available. Just add your image like so: $ build/cbfstool build/coreboot.rom \ add -n background.png -t raw -f $ build/cbfstool build/coreboot.rom \ print Some T400 machines come with extended screen resolution 1440x900px. You may add up to three more images named `background_1.png`, `background_2.png` and `background_3.png`. This feature provides space for additional information, such as a documented flash procedure for example. Use hotkey 'b' in GRUB’s Boot Menu to cycle through the images. ### Add Descriptor and GbE File See [How To Modify The Intel Flash Descriptor][how-to-modify-ifd] for reference. Now add the previously generated descriptor+gbe to your ROM image, adapt paths as needed: $ dd \ if=ich9fdgbe_8m.bin \ of=coreboot.rom \ bs=1 count=12k conv=notrunc NOTE: This T400 still has its IME architecture on board and it is unknown to the public which basic features might be hardwired. It would be safer *not* to install the GbE binary blob using the “...fdnogbe...” binaries. However, this doesn't seem to work with this How-to. Tweak Parameters in `cmos.default` ---------------------------------- Tweak parameter `gfx_uma_size` and `wwan` in the ROM’s `cmos.default` file: $ build/util/nvramtool/nvramtool -C build/coreboot.rom -w gfx_uma_size=256M $ build/util/nvramtool/nvramtool -C build/coreboot.rom -w wwan=Disable $ build/util/nvramtool/nvramtool -C build/coreboot.rom -w bluetooth=Disable Inquire parameter’s possible values with option `-e`, i.e.: $ build/util/nvramtool/nvramtool -C build/coreboot.rom -e gfx_uma_size Our “standard” CMOS setup now looks like this: $ build/util/nvramtool/nvramtool -C build/coreboot.rom -a boot_option = Fallback reboot_counter = 0x0 debug_level = Spew sata_mode = AHCI power_on_after_fail = Disable first_battery = Primary bluetooth = Disable wwan = Disable wlan = Enable trackpoint = Enable volume = 0x3 fn_ctrl_swap = Disable sticky_fn = Disable power_management_beeps = Enable low_battery_beep = Enable uwb = Disable boot_devices = boot_default = 0x0 gfx_uma_size = 256M NOTE: You will be able to modify these settings with the NVRAMCUI Payload upon boot time. Done! ----- Your ROM should now be ready to go! Don't forget to reset the checksum of the NVRAM Option Table to zero by unplugging the small coin battery for some seconds. [how-to-modify-ifd]: ../doc/how-to-modify-ifd.md [GRUB How-To]: ../doc/grub-how-to.md [Coreinfo CPU Exceptions]: ../doc/coreinfo-cpu-exceptions.md [grub@2.02_zerocat.cfg]: ../templates/grub@2.02_zerocat.cfg