NAME

       kwboot - Boot Marvell Kirkwood (and others 32-bit) SoCs over a serial link.

SYNOPSIS

       kwboot [-b image] [-t] [-B baudrate] TTY

DESCRIPTION

       The  kwboot program boots boards based on Marvell's 32-bit platforms including Kirkwood, Dove, A370, AXP,
       A375, A38x and A39x over their integrated UART. Boot image files will typically contain  a  second  stage
       boot  loader,  such  as  U-Boot.  The  image file must conform to Marvell's BootROM firmware image format
       (kwbimage v0 or v1), created using a tool such as mkimage.

       Following power-up or a system reset, system BootROM code polls the UART for  a  brief  period  of  time,
       sensing  a  handshake message which initiates an image upload. This program sends this boot message until
       it receives a positive acknowledgement. The image is transferred using Xmodem.

       Additionally, this program implements a minimal terminal mode, which can be used  either  standalone,  or
       entered  immediately  following  boot image transfer completion. This is often useful to catch early boot
       messages, or to manually interrupt a default boot procedure performed by the second-stage loader.

OPTIONS

       -b image
              Handshake; then upload file image over TTY.

              Note that for the encapsulated boot code to be executed, image must be of type "UART boot" (0x69).
              The kwboot program changes this type automatically, unless the image is signed, in which  case  it
              cannot be changed.

              This  mode  writes  handshake status and upload progress indication to stdout. It is possible that
              image contains an optional binary code in it's header which may also print some  output  via  UART
              (for  example  U-Boot  SPL does this). In such a case, this output is also written to stdout after
              the header is sent.

       -p     Obsolete. Does nothing.

              In the past, when this option was used, the program patched the header in the image prior  upload,
              to "UART boot" type. This is now done by default.

       -t     Run a terminal program, connecting standard input and output to TTY.

              If  used in combination with -b, terminal mode is entered immediately following a successful image
              upload.

              If standard I/O streams connect to a console, this mode  will  terminate  after  receiving  ctrl-\
              followed by c from console input.

       -B baudrate
              If  used  in  combination  with  -b,  inject  into the image header code that changes baud rate to
              baudrate after uploading image header, and code that changes the baud rate  back  to  the  default
              (115200  Bd)  before executing payload, and also adjust the baud rate on TTY correspondingly. This
              can make the upload significantly faster.

              If used in combination with -t, adjust the baud rate to baudrate on TTY before starting terminal.

              If both -b and -t are used, the baud rate is changed back to 115200 after the upload.

              Tested values for baudrate for Armada 38x include: 115200, 230400, 460800, 500000, 576000, 921600,
              1000000, 1152000, 1500000, 2000000, 2500000, 3125000, 4000000 and 5200000.

SEE ALSO

       mkimage(1)

AUTHORS

       Daniel Stodden <daniel.stodden@gmail.com>
       Luka Perkov <luka@openwrt.org>
       David Purdy <david.c.purdy@gmail.com>
       Pali Rohár <pali@kernel.org>
       Marek Behún <marek.behun@nic.cz>

                                                   2021-08-25                                          KWBOOT(1)