fastboot - platform/system/core - Git at Google

getvar:%s          Read a config/version variable from the bootloader.
                   The variable contents will be returned after the
                   OKAY response. If the variable is unknown, the bootloader
                   should return a FAIL response, optionally with an error
                   message.

                   Previous versions of this document indicated that getvar
                   should return an empty OKAY response for unknown
                   variables, so older devices might exhibit this behavior,
                   but new implementations should return FAIL instead.

download:%08x      Write data to memory which will be later used
                   by "boot", "ramdisk", "flash", etc.  The client
                   will reply with "DATA%08x" if it has enough
                   space in RAM or "FAIL" if not.  The size of
                   the download is remembered.

upload             Read data from memory which was staged by the last
                   command, e.g. an oem command.  The client will reply
                   with "DATA%08x" if it is ready to send %08x bytes of
                   data.  If no data was staged in the last command,
                   the client must reply with "FAIL".  After the client
                   successfully sends %08x bytes, the client shall send
                   a single packet starting with "OKAY".  Clients
                   should not support "upload" unless it supports an
                   oem command that requires "upload" capabilities.

flash:%s           Write the previously downloaded image to the
                   named partition (if possible).

erase:%s           Erase the indicated partition (clear to 0xFFs)

boot               The previously downloaded data is a boot.img
                   and should be booted according to the normal
                   procedure for a boot.img

continue           Continue booting as normal (if possible)

reboot             Reboot the device.

reboot-bootloader
                   Reboot back into the bootloader.
                   Useful for upgrade processes that require upgrading
                   the bootloader and then upgrading other partitions
                   using the new bootloader.