1  # Lenovo M920 Tiny
  2  
  3  This page describes how to run coreboot on Lenovo M920 Tiny (M920q, M920x).
  4  
  5  ## Technology
  6  
  7  ```{eval-rst}
  8  +------------+---------------------------------------------------------------+
  9  | CPU        | Intel Core 8th Gen  or 9th Gen (Coffee Lake (Refresh))        |
 10  +------------+---------------------------------------------------------------+
 11  | DRAM       | 2 SO-DIMM slots, DDR4-2400/2666                               |
 12  +------------+---------------------------------------------------------------+
 13  | Chipset    | Intel Q370                                                    |
 14  +------------+---------------------------------------------------------------+
 15  | Super I/O  | NCT6686D-L                                                    |
 16  +------------+---------------------------------------------------------------+
 17  | TPM        | Infineon SLB 9670VQ2.0                                        |
 18  +------------+---------------------------------------------------------------+
 19  | Boot       | USB, SATA (on-board SATA1 port, M.2 ports), NVMe              |
 20  +------------+---------------------------------------------------------------+
 21  | Power      | 65-135 W power adapter                                        |
 22  +------------+---------------------------------------------------------------+
 23  ```
 24  
 25  More specifications on [Lenovo M920 Tiny specifications].
 26  
 27  ## Flashing coreboot
 28  
 29  ```{eval-rst}
 30  +---------------------+--------------------------+
 31  | Type                | Value                    |
 32  +=====================+==========================+
 33  | Socketed flash      | no                       |
 34  +---------------------+--------------------------+
 35  | Model               | W25Q128JV + W25Q64JV     |
 36  +---------------------+--------------------------+
 37  | Size                | 16 + 8 MiB               |
 38  +---------------------+--------------------------+
 39  | Package             | SOIC-8 + SOIC-8          |
 40  +---------------------+--------------------------+
 41  | Write protection    | chipset PRR              |
 42  +---------------------+--------------------------+
 43  | Dual BIOS feature   | no                       |
 44  +---------------------+--------------------------+
 45  | Internal flashing   | after flashing coreboot  |
 46  +---------------------+--------------------------+
 47  ```
 48  
 49  ### Internal programming
 50  
 51  The SPI flash can be accessed using [flashrom].
 52  
 53      flashrom -p internal -N -w coreboot.rom --ifd -i bios
 54  
 55  Internal programming can be used after the coreboot has been flashed externally
 56  for the first time. Internal programming when migrating from original UEFI
 57  firmware **has not been tested**.
 58  
 59  ### External programming
 60  
 61  The external access to flash chip is available through standard SOP-8 clip. The
 62  voltage of both SPI chips is 3.3V.
 63  
 64  It is recommended to flash firmware without supplying power from power adapter.
 65  
 66  The resulting coreboot.rom file must be split into two binaries, one for each
 67  flash chip:
 68  
 69      dd if=build/coreboot.rom of=build/coreboot_flash_1.rom bs=16M count=1
 70      dd if=build/coreboot.rom of=build/coreboot_flash_2.rom bs=8M skip=2
 71  
 72  The flash chips are marked on the mainboard as BIOS1 and BIOS2 respectively.
 73  They can be flashed with following commands:
 74  
 75      flashrom -p ch341a_spi -w build/coreboot_flash_1.rom
 76      flashrom -p ch341a_spi -w build/coreboot_flash_2.rom -c "W25Q64JV-.Q"
 77  
 78  ## Known issues
 79  
 80  - front audio jacks do not work
 81  
 82  ## Working
 83  
 84  Tested with edk2 payload (mrchromebox) and Ubuntu 22.04 (Linux 6.2.0):
 85  
 86  - Serial adapter from daughter board (COM1 connector)
 87  - USB 3.0 and 2.0 rear and front ports (edk2 and Linux 6.2.0)
 88  - USB-C port (charging, data)
 89  - Gigabit Ethernet
 90  - SATA
 91  - internal speaker
 92  - TPM2.0
 93  - WiFi slot
 94  - HDMI
 95  - NVMe
 96  - PCIe x8 port
 97    - PCIe x8 tested using BA7H70 Rev 1.2 riser and Intel X540-T2 10G dual 10GbE card
 98    - another riser with PCIe x4 connector remains untested - please modify this
 99      page if you do test it!
100  
101  [flashrom]: https://flashrom.org/Flashrom
102  [Lenovo M920 Tiny specifications]: https://psref.lenovo.com/syspool/Sys/PDF/ThinkCentre/ThinkCentre_M920_Tiny/ThinkCentre_M920_Tiny_Spec.PDF