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Diffstat (limited to 'Documentation/driver-api/mtd/intel-spi.rst')
| -rw-r--r-- | Documentation/driver-api/mtd/intel-spi.rst | 90 |
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diff --git a/Documentation/driver-api/mtd/intel-spi.rst b/Documentation/driver-api/mtd/intel-spi.rst deleted file mode 100644 index 0465f6879262..000000000000 --- a/Documentation/driver-api/mtd/intel-spi.rst +++ /dev/null @@ -1,90 +0,0 @@ -============================== -Upgrading BIOS using intel-spi -============================== - -Many Intel CPUs like Baytrail and Braswell include SPI serial flash host -controller which is used to hold BIOS and other platform specific data. -Since contents of the SPI serial flash is crucial for machine to function, -it is typically protected by different hardware protection mechanisms to -avoid accidental (or on purpose) overwrite of the content. - -Not all manufacturers protect the SPI serial flash, mainly because it -allows upgrading the BIOS image directly from an OS. - -The intel-spi driver makes it possible to read and write the SPI serial -flash, if certain protection bits are not set and locked. If it finds -any of them set, the whole MTD device is made read-only to prevent -partial overwrites. By default the driver exposes SPI serial flash -contents as read-only but it can be changed from kernel command line, -passing "intel-spi.writeable=1". - -Please keep in mind that overwriting the BIOS image on SPI serial flash -might render the machine unbootable and requires special equipment like -Dediprog to revive. You have been warned! - -Below are the steps how to upgrade MinnowBoard MAX BIOS directly from -Linux. - - 1) Download and extract the latest Minnowboard MAX BIOS SPI image - [1]. At the time writing this the latest image is v92. - - 2) Install mtd-utils package [2]. We need this in order to erase the SPI - serial flash. Distros like Debian and Fedora have this prepackaged with - name "mtd-utils". - - 3) Add "intel-spi.writeable=1" to the kernel command line and reboot - the board (you can also reload the driver passing "writeable=1" as - module parameter to modprobe). - - 4) Once the board is up and running again, find the right MTD partition - (it is named as "BIOS"):: - - # cat /proc/mtd - dev: size erasesize name - mtd0: 00800000 00001000 "BIOS" - - So here it will be /dev/mtd0 but it may vary. - - 5) Make backup of the existing image first:: - - # dd if=/dev/mtd0ro of=bios.bak - 16384+0 records in - 16384+0 records out - 8388608 bytes (8.4 MB) copied, 10.0269 s, 837 kB/s - - 6) Verify the backup:: - - # sha1sum /dev/mtd0ro bios.bak - fdbb011920572ca6c991377c4b418a0502668b73 /dev/mtd0ro - fdbb011920572ca6c991377c4b418a0502668b73 bios.bak - - The SHA1 sums must match. Otherwise do not continue any further! - - 7) Erase the SPI serial flash. After this step, do not reboot the - board! Otherwise it will not start anymore:: - - # flash_erase /dev/mtd0 0 0 - Erasing 4 Kibyte @ 7ff000 -- 100 % complete - - 8) Once completed without errors you can write the new BIOS image:: - - # dd if=MNW2MAX1.X64.0092.R01.1605221712.bin of=/dev/mtd0 - - 9) Verify that the new content of the SPI serial flash matches the new - BIOS image:: - - # sha1sum /dev/mtd0ro MNW2MAX1.X64.0092.R01.1605221712.bin - 9b4df9e4be2057fceec3a5529ec3d950836c87a2 /dev/mtd0ro - 9b4df9e4be2057fceec3a5529ec3d950836c87a2 MNW2MAX1.X64.0092.R01.1605221712.bin - - The SHA1 sums should match. - - 10) Now you can reboot your board and observe the new BIOS starting up - properly. - -References ----------- - -[1] https://firmware.intel.com/sites/default/files/MinnowBoard%2EMAX_%2EX64%2E92%2ER01%2Ezip - -[2] http://www.linux-mtd.infradead.org/ |