1U-Boot for the Freescale i.MX6q SabreLite board
2===============================================
3
4This file contains information for the port of U-Boot to the Freescale
5i.MX6q SabreLite board.
6
7
81. Build
9--------
10
11To build U-Boot for the SabreLite board:
12
13 make mx6qsabrelite_config
14 make
15
16
172. Boot from SD card
18--------------------
19
20The SabreLite boards boot from the SPI NOR flash. These boards need their SPI
21to be reflashed with a small SD card loader to support boot from SD card. The
22board will still boot from SPI NOR, but the loader will in turn request the
23BootROM to load the U-Boot from SD card.
24
25The SD card loader is available from
26
27https://wiki.linaro.org/Boards/MX6QSabreLite
28
29This is provided under a open-source 3-clause BSD license.
30
31To following procedure can be used to update the SPI-NOR on the SabreLite
32board:
33
341. Write this SD card loader onto a large SD card using:
35
36      sudo dd if=iMX6DQ_SPI_to_uSDHC3.bin of=/dev/sXx
37
38   Note: Replace sXx with the device representing the SD card in your system.
39
40   Note: This writes SD card loader at address 0
41
422. Put this SD card into the slot for the large SD card (SD3 on the bottom of
43   the board). Make sure SW1 switch is at position "00", so that it can boot
44   from the fuses.
45
463. Power-up the SabreLite, press 'space' to enter command mode in the U-Boot
47   (the default one the board is shipped with, starting from the SPI NOR) and
48   enter the following commands:
49
50      MX6Q SABRELITE U-Boot > mmc dev 0
51      MX6Q SABRELITE U-Boot > mmc read 0x10800000 0 200
52      MX6Q SABRELITE U-Boot > sf probe
53      MX6Q SABRELITE U-Boot > sf erase 0 0x40000
54      MX6Q SABRELITE U-Boot > sf write 0x10800000 0 0x40000
55
564. Write the u-boot.imx produced during the U-Boot build to the SD card:
57
58      sudo dd if=u-boot.imx of=/dev/sXx bs=512 seek=2 && sudo sync
59
60   Note: Replace sXx with the device representing the SD card in your system.
61
625. Re-insert the SD card back in the slot for the large SD card and power-cycle
63   the board.
64
65Note: The board now boots from full size SD3 on the bottom of the board. NOT
66      the micro SD4/BOOT slot on the top of the board. I.e. you have to use
67      full size SD cards.
68
69This information originally taken from:
70
71   https://wiki.linaro.org/Boards/MX6QSabreLite
72
73
743. Boot from SPI NOR
75--------------------
76
77The SabreLite board can also boot U-Boot directly from the SPI NOR flash:
78
791. Power-up the SabreLite, press 'space' to enter command mode in the U-Boot
80   and enter the following commands:
81
82      => mmc dev 0
83      => mmc read 0x10800000 0x400 0x80000
84      => sf probe 0
85      => sf erase 0 0xc0000
86      => sf write 0x10800000 0x400 0x80000
87
88Note: This procedure assumes you have booted using the desired U-Boot from an
89      SD card as prepared in the previous section. Alternative mechanisms, such
90      as using tftpboot to copy an alternative U-Boot image into memory can
91      also be used.
92
93
944. Recovering SPI-NOR
95---------------------
96
97In case you somehow do not succeed with this procedure you can upload U-Boot
98via USB:
99
1001. Download and install the imx_loader following the instructions provided:
101
102      https://github.com/boundarydevices/imx_usb_loader
103
1042. Connect the board to USB via the USB OTG port.
105
1063. Make sure SW1 switch is at position "01", so that it can boot from USB OTG.
107
1084. Power-up the SabreLite and run the imx_loader to upload the U-Boot image:
109
110      sudo imx_usb u-boot.imx
111
112Note: This will upload and run the U-Boot image in memory, the SPI will not be
113      reprogrammed and this procedure will need to be repeated if the board is
114      reset.
115
1165. Use one of previous descriptions to re-flash the SPI-NOR as required.
117
1186. Ensure SW1 is returned to "00" to boot from the fuses once done.
119
120