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)