Flashrom
Flashrom is a utility to read flash.
Cheat sheet[edit | edit source]
| Task | Command |
|---|---|
| Dump a ROM connected via SPI | flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -r dump.bin
|
| Dump a ROM via SPI using a specific chip definition | flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=600 -c "MX25L12835F/MX25L12845E/MX25L12865E" -w dump.bin
|
| Write a ROM via SPI | flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=32768 -w new-data-to-rom.bin
|
Using flashrom with a Raspberry Pi[edit | edit source]
Compile and install[edit | edit source]
# apt-get install build-essential pciutils usbutils libpci-dev libusb-dev libftdi1 libftdi-dev zlib1g-dev
# git clone https://github.com/flashrom/flashrom.git
# cd flashrom
# make CONFIG_ENABLE_LIBUSB1_PROGRAMMERS=no
Pinouts[edit | edit source]
Refer to the table below and the diagram on the right for the pinouts to your Raspberry Pi and the SPI rom device.
| RPi header | SPI Function | MX25L 16-Pin SOP | HM25Q 8-Pin SOP |
|---|---|---|---|
| 25 | GND | 10 | 4 |
| 24 | CS | 7 | 1 |
| 23 | SCK (CLK) | 16 | 6 |
| 21 | DO (MISO) | 8 | 2 |
| 19 | DI (MOSI) | 15 | 5 |
| 17 | VCC 3.3v | 2 | 8 |
| WP# | 9 | 3 | |
| HOLD# / RESET# | 3 | 7 |
The MX25L - WriteProtect (WP#, pin 9) should be connected to GND according to the datasheet. Leaving it floating still seems to work.
The Raspberry Pi should have SPI enabled by adding this line to /boot/config.txt:
dtparam=spi=on
The /dev/spidev0.0 device should exist and flashrom should be able to detect the flash chip.
[root@alarmpi alarm]# flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=1000
flashrom v1.0 on Linux 4.14.92-1-ARCH (armv7l)
flashrom is free software, get the source code at https://flashrom.org
Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Macronix flash chip "MX25L12805D" (16384 kB, SPI) on linux_spi.
Found Macronix flash chip "MX25L12835F/MX25L12845E/MX25L12865E" (16384 kB, SPI) on linux_spi.
Multiple flash chip definitions match the detected chip(s): "MX25L12805D", "MX25L12835F/MX25L12845E/MX25L12865E"
Please specify which chip definition to use with the -c <chipname> option.
Dump the data using -r filename.
[root@alarmpi alarm]# flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=300 -c "MX25L12835F/MX25L12845E/MX25L12865E" -r dump7.dat
flashrom v1.0 on Linux 4.14.92-1-ARCH (armv7l)
flashrom is free software, get the source code at https://flashrom.org
Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Macronix flash chip "MX25L12835F/MX25L12845E/MX25L12865E" (16384 kB, SPI) on linux_spi.
Reading flash... done.
Troubleshooting[edit | edit source]
Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI) on linux_spi.[edit | edit source]
I connected a T25S80 to the Raspberry Pi but when I run flashrom, I get a "unknown SPI chip" message:
# flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=1000
flashrom v1.2 on Linux 5.10.63-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org
Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI) on linux_spi.
Running with -VVV prints a bit more information:
...
Probing for Winbond unknown Winbond (ex Nexcom) SPI chip, 0 kB: RDID returned 0x5e 0x32 0x14. probe_spi_rdid_generic: id1 0x5e, id2 0x3214
Probing for Generic unknown SPI chip (RDID), 0 kB: RDID returned 0x5e 0x32 0x14. probe_spi_rdid_generic: id1 0x5e, id2 0x3214
Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI) on linux_spi.
Probing for Generic unknown SPI chip (REMS), 0 kB: REMS returned 0x5e 0x13. probe_spi_rems: id1 0x5e, id2 0x13
Found Generic flash chip "unknown SPI chip (RDID)" (0 kB, SPI).
The message shows the RDID value as being 0x5e 0x32 0x14.
Knowing that the chip I'm dealing with is virtually identical to the NANTRONICS N25S80, I went ahead and edited flashchips.h such that the ID and chip identifiers matched 0x5e and 0x3214:
#define NANTRONICS_ID_NOPREFIX 0x5E
#define NANTRONICS_N25S10 0x3011
#define NANTRONICS_N25S20 0x3012
#define NANTRONICS_N25S40 0x3013
#define NANTRONICS_N25S80 0x3214
#define NANTRONICS_N25S16 0x3015
Recompile flashrom and try again:
# ./flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=1600
flashrom v1.2-555-g073e205-dirty on Linux 5.10.63-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org
Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Nantronics flash chip "N25S80" (1024 kB, SPI) on linux_spi.
I was then able to dump the flash. Yippie.