Hi Priit,
On Wed, 24 Oct 2018 at 04:21, Priit Laes plaes@plaes.org wrote:
From: Priit Laes priit.laes@paf.com
Signed-off-by: Priit Laes plaes@plaes.org
board/sunxi/README.fastboot | 98 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 98 insertions(+) create mode 100644 board/sunxi/README.fastboot
diff --git a/board/sunxi/README.fastboot b/board/sunxi/README.fastboot new file mode 100644 index 0000000..470fa6f --- /dev/null +++ b/board/sunxi/README.fastboot @@ -0,0 +1,98 @@ +Using fastboot on sunxi devices +===============================
+Fastboot is a diagnostic protocol, primarily used to modify the +filesystems on the flash device via USB or UDP. It requires that +the device is started in a boot loader or Seconday Boot Loader mode.
"Seconday" -> "Secondary"
+This document currently walks through an installation with a device +with eMMC storage.
+Prerequisites +-------------
+* fastboot binaries installed on client machine +* sunxi-tools installed on client machine (optional) +* u-boot tools (mkimage) +* u-boot binaries for the target sunxi device +* filesystem images
- root file system containing operating system
- vfat file system
+* Sunxi device connected to client via OTG port
+Getting your device into Fastboot mode +--------------------------------------
+To enter into fastboot mode, execute the `fastboot` command in +U-Boot:
+$ fastboot usb 0
+On the client machine, you can check whether the device is visible +using the `fastboot devices` command. And for fun, you can also +fetch the bootloader version using the fastboot protocol:
+$ fastboot devices +1234567890abcdef fastboot +$ fastboot getvar bootloader-version +bootloader-version: U-Boot 2018.11-rc2-00033-ge3beca3a2f +finished. total time: 0.000s
+Preparing the device for flashing +---------------------------------
+Now that the device is in the fastboot mode, we can continue with +creating the partitions on the device. By default, u-boot for sunxi +defines following partitions:
+* loader1 - partition for secondary program loader +* loader2 - partition for u-boot +* esp - EFI system partition, also used for u-boot to look up boot.scr +* system - Root partition for system
+These partitions have also assigned GUID's according to Discoverable +Partitions Specification [1], to enable automatic discovery of partitions +and their mountpoints.
+You can start by formatting the internal storage by executing the +`fastboot oem format` command from client:
+$ fastboot oem format
+This equivalent to running the `gpt write mmc 1 $partitions` from u-boot.
+[1] https://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/
+Flashing the device +-------------------
+Now that we have the partitions created, all that is left for us +is to flash the data.
+`loader1` is used for storing the Seconday Program Loader, in our +case, it is the `spl/sunxi-spl.bin` in the u-boot directory:
"Seconday" -> "Secondary"
+$ fastboot flash loader1 spl/sunxi-spl.bin
+`loader2` is for storing the u-boot binary. `u-boot.img` in the +u-boot source directory:
+$ fastboot flash loader2 u-boot.img
+`esp` partition (EFI System Partition) can be kept empty, although +if it is VFAT partition, u-boot automatically looks up the `boot.scr` +file for device-specific configuration. (You can create empty vfat +partition by `fallocate -l 32M esp.img && mkfs.vfat esp.img`)
+$ fastboot flash esp esp.img
+`system` partition is where the operating system resides. Creating +that is left as an exercise to the reader.
+$ fastboot flash system system.img
+Now, if everything has been properly set up (aka proper kernel +with machine-specific dtb installed on system.img, and boot.scr +on esp partition), you can reboot the machine:
+$ fastboot reboot
git-series 0.9.1
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Regards, Jonathan