1 ==============================
2 Upgrading BIOS using spi-intel
3 ==============================
4
5 Many Intel CPUs like Baytrail and Braswell inc
6 controller which is used to hold BIOS and othe
7 Since contents of the SPI serial flash is cruc
8 it is typically protected by different hardwar
9 avoid accidental (or on purpose) overwrite of
10
11 Not all manufacturers protect the SPI serial f
12 allows upgrading the BIOS image directly from
13
14 The spi-intel driver makes it possible to read
15 flash, if certain protection bits are not set
16 any of them set, the whole MTD device is made
17 partial overwrites. By default the driver expo
18 contents as read-only but it can be changed fr
19 passing "spi_intel.writeable=1".
20
21 Please keep in mind that overwriting the BIOS
22 might render the machine unbootable and requir
23 Dediprog to revive. You have been warned!
24
25 Below are the steps how to upgrade MinnowBoard
26 Linux.
27
28 1) Download and extract the latest Minnowboar
29 [1]. At the time writing this the latest i
30
31 2) Install mtd-utils package [2]. We need thi
32 serial flash. Distros like Debian and Fedo
33 name "mtd-utils".
34
35 3) Add "spi_intel.writeable=1" to the kernel
36 the board (you can also reload the driver
37 module parameter to modprobe).
38
39 4) Once the board is up and running again, fi
40 (it is named as "BIOS")::
41
42 # cat /proc/mtd
43 dev: size erasesize name
44 mtd0: 00800000 00001000 "BIOS"
45
46 So here it will be /dev/mtd0 but it may va
47
48 5) Make backup of the existing image first::
49
50 # dd if=/dev/mtd0ro of=bios.bak
51 16384+0 records in
52 16384+0 records out
53 8388608 bytes (8.4 MB) copied, 10.0269
54
55 6) Verify the backup::
56
57 # sha1sum /dev/mtd0ro bios.bak
58 fdbb011920572ca6c991377c4b418a0502668b
59 fdbb011920572ca6c991377c4b418a0502668b
60
61 The SHA1 sums must match. Otherwise do not
62
63 7) Erase the SPI serial flash. After this ste
64 board! Otherwise it will not start anymore
65
66 # flash_erase /dev/mtd0 0 0
67 Erasing 4 Kibyte @ 7ff000 -- 100 % com
68
69 8) Once completed without errors you can writ
70
71 # dd if=MNW2MAX1.X64.0092.R01.1605221712.b
72
73 9) Verify that the new content of the SPI ser
74 BIOS image::
75
76 # sha1sum /dev/mtd0ro MNW2MAX1.X64.009
77 9b4df9e4be2057fceec3a5529ec3d950836c87
78 9b4df9e4be2057fceec3a5529ec3d950836c87
79
80 The SHA1 sums should match.
81
82 10) Now you can reboot your board and observe
83 properly.
84
85 References
86 ----------
87
88 [1] https://firmware.intel.com/sites/default/f
89
90 [2] http://www.linux-mtd.infradead.org/
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