1*4ab13489SMika Westerberg============================== 2*4ab13489SMika WesterbergUpgrading BIOS using spi-intel 3*4ab13489SMika Westerberg============================== 4*4ab13489SMika Westerberg 5*4ab13489SMika WesterbergMany Intel CPUs like Baytrail and Braswell include SPI serial flash host 6*4ab13489SMika Westerbergcontroller which is used to hold BIOS and other platform specific data. 7*4ab13489SMika WesterbergSince contents of the SPI serial flash is crucial for machine to function, 8*4ab13489SMika Westerbergit is typically protected by different hardware protection mechanisms to 9*4ab13489SMika Westerbergavoid accidental (or on purpose) overwrite of the content. 10*4ab13489SMika Westerberg 11*4ab13489SMika WesterbergNot all manufacturers protect the SPI serial flash, mainly because it 12*4ab13489SMika Westerbergallows upgrading the BIOS image directly from an OS. 13*4ab13489SMika Westerberg 14*4ab13489SMika WesterbergThe spi-intel driver makes it possible to read and write the SPI serial 15*4ab13489SMika Westerbergflash, if certain protection bits are not set and locked. If it finds 16*4ab13489SMika Westerbergany of them set, the whole MTD device is made read-only to prevent 17*4ab13489SMika Westerbergpartial overwrites. By default the driver exposes SPI serial flash 18*4ab13489SMika Westerbergcontents as read-only but it can be changed from kernel command line, 19*4ab13489SMika Westerbergpassing "spi_intel.writeable=1". 20*4ab13489SMika Westerberg 21*4ab13489SMika WesterbergPlease keep in mind that overwriting the BIOS image on SPI serial flash 22*4ab13489SMika Westerbergmight render the machine unbootable and requires special equipment like 23*4ab13489SMika WesterbergDediprog to revive. You have been warned! 24*4ab13489SMika Westerberg 25*4ab13489SMika WesterbergBelow are the steps how to upgrade MinnowBoard MAX BIOS directly from 26*4ab13489SMika WesterbergLinux. 27*4ab13489SMika Westerberg 28*4ab13489SMika Westerberg 1) Download and extract the latest Minnowboard MAX BIOS SPI image 29*4ab13489SMika Westerberg [1]. At the time writing this the latest image is v92. 30*4ab13489SMika Westerberg 31*4ab13489SMika Westerberg 2) Install mtd-utils package [2]. We need this in order to erase the SPI 32*4ab13489SMika Westerberg serial flash. Distros like Debian and Fedora have this prepackaged with 33*4ab13489SMika Westerberg name "mtd-utils". 34*4ab13489SMika Westerberg 35*4ab13489SMika Westerberg 3) Add "spi_intel.writeable=1" to the kernel command line and reboot 36*4ab13489SMika Westerberg the board (you can also reload the driver passing "writeable=1" as 37*4ab13489SMika Westerberg module parameter to modprobe). 38*4ab13489SMika Westerberg 39*4ab13489SMika Westerberg 4) Once the board is up and running again, find the right MTD partition 40*4ab13489SMika Westerberg (it is named as "BIOS"):: 41*4ab13489SMika Westerberg 42*4ab13489SMika Westerberg # cat /proc/mtd 43*4ab13489SMika Westerberg dev: size erasesize name 44*4ab13489SMika Westerberg mtd0: 00800000 00001000 "BIOS" 45*4ab13489SMika Westerberg 46*4ab13489SMika Westerberg So here it will be /dev/mtd0 but it may vary. 47*4ab13489SMika Westerberg 48*4ab13489SMika Westerberg 5) Make backup of the existing image first:: 49*4ab13489SMika Westerberg 50*4ab13489SMika Westerberg # dd if=/dev/mtd0ro of=bios.bak 51*4ab13489SMika Westerberg 16384+0 records in 52*4ab13489SMika Westerberg 16384+0 records out 53*4ab13489SMika Westerberg 8388608 bytes (8.4 MB) copied, 10.0269 s, 837 kB/s 54*4ab13489SMika Westerberg 55*4ab13489SMika Westerberg 6) Verify the backup:: 56*4ab13489SMika Westerberg 57*4ab13489SMika Westerberg # sha1sum /dev/mtd0ro bios.bak 58*4ab13489SMika Westerberg fdbb011920572ca6c991377c4b418a0502668b73 /dev/mtd0ro 59*4ab13489SMika Westerberg fdbb011920572ca6c991377c4b418a0502668b73 bios.bak 60*4ab13489SMika Westerberg 61*4ab13489SMika Westerberg The SHA1 sums must match. Otherwise do not continue any further! 62*4ab13489SMika Westerberg 63*4ab13489SMika Westerberg 7) Erase the SPI serial flash. After this step, do not reboot the 64*4ab13489SMika Westerberg board! Otherwise it will not start anymore:: 65*4ab13489SMika Westerberg 66*4ab13489SMika Westerberg # flash_erase /dev/mtd0 0 0 67*4ab13489SMika Westerberg Erasing 4 Kibyte @ 7ff000 -- 100 % complete 68*4ab13489SMika Westerberg 69*4ab13489SMika Westerberg 8) Once completed without errors you can write the new BIOS image:: 70*4ab13489SMika Westerberg 71*4ab13489SMika Westerberg # dd if=MNW2MAX1.X64.0092.R01.1605221712.bin of=/dev/mtd0 72*4ab13489SMika Westerberg 73*4ab13489SMika Westerberg 9) Verify that the new content of the SPI serial flash matches the new 74*4ab13489SMika Westerberg BIOS image:: 75*4ab13489SMika Westerberg 76*4ab13489SMika Westerberg # sha1sum /dev/mtd0ro MNW2MAX1.X64.0092.R01.1605221712.bin 77*4ab13489SMika Westerberg 9b4df9e4be2057fceec3a5529ec3d950836c87a2 /dev/mtd0ro 78*4ab13489SMika Westerberg 9b4df9e4be2057fceec3a5529ec3d950836c87a2 MNW2MAX1.X64.0092.R01.1605221712.bin 79*4ab13489SMika Westerberg 80*4ab13489SMika Westerberg The SHA1 sums should match. 81*4ab13489SMika Westerberg 82*4ab13489SMika Westerberg 10) Now you can reboot your board and observe the new BIOS starting up 83*4ab13489SMika Westerberg properly. 84*4ab13489SMika Westerberg 85*4ab13489SMika WesterbergReferences 86*4ab13489SMika Westerberg---------- 87*4ab13489SMika Westerberg 88*4ab13489SMika Westerberg[1] https://firmware.intel.com/sites/default/files/MinnowBoard%2EMAX_%2EX64%2E92%2ER01%2Ezip 89*4ab13489SMika Westerberg 90*4ab13489SMika Westerberg[2] http://www.linux-mtd.infradead.org/ 91