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OpenIPC Wiki

Table of Content

Help: U-Boot

Prepare the environment

In booloader shell, check if baseaddr variable is already defined.

printenv baseaddr

If it is not there, set it yourself.

# Look up address for your SoC at https://openipc.org/supported-hardware/
setenv baseaddr 0x80600000

Assign the hex size of your flash chip to a variable called flashsize.

# Use 0x800000 for an 8MB flash chip, 0x1000000 for 16MB.
setenv flashsize 0x800000

Save these values into the environment afterwards.

saveenv

Saving original firmware without using TFTP.

Before you start, prepare the environment.

In the terminal program that you use to connect to the UART port, enable saving log file of the session. I like to use screen for this and my command for connect to the UART adapter with logging the active session to a file would look like this:

screen -L -Logfile fulldump.log /dev/ttyUSB0 115200

After connecting to the bootloader console, run a set of commands for reading whole amount of data from flash memory chip into RAM, and then dumping it as hexadecimal values into terminal window.

mw.b ${baseaddr} 0xff ${flashsize}
sf probe 0
sf read ${baseaddr} 0x0 ${flashsize}
md.b ${baseaddr} ${flashsize}

Since the process of reading is going to take a considerable amount of time (literally hours), you might want to disconnect from the terminal session to avoid accidental keystrokes contaminating the output. Press Ctrl-a followed by d to detach the session from active terminal. Run screen -r when you need to reconnect it later, after the size of the log file will stop growing. Reading of an 8 MB flash memory should result in a ~40 MB log file, and for a 16 MB chip the file should be twice that size.

Convert the hex dump into a binary firmware file and use it for further research or restoring camera to its pristine state.

cat fulldump.log | sed -E "s/^[0-9a-f]{8}\b: //i" | sed -E "s/ {4}.{16}\r?$//" > fulldump.hex
xxd -revert -plain fulldump.hex fulldump.bin

Use binwalk to unpack the binary file.

Saving firmware via SD card.

Before you start, prepare the environment.

Sometimes your camera only has a wireless connection, which does not work directly from the bootloader. Very often such cameras have a microSD card slot. In this case you can try to save a copy of the original firmware using an SD card as an intermediary medium.

Since you're going to save firmware in its binary form, the amount of data will be either 8 MB or 16 MB, depending on the size of camera's flash memory chip. So any SD card will do, even the smallest one.

Insert the card into the card slot on the camera, connect the serial adapter to the UART port, supply power to the camera and stop the boot process to get into the bootloader console.

Initialize access to the card, and clear some space to save firmware on. Data is written onto card in blocks of 512 bytes. You need to erase 16384 blocks to clear 8 MB, 32768 blocks for 16 MB, which are 0x4000 and 0x8000 hexadecimal, respectively.

Note that we are going to write directly to the card registers, bypassing the partition table. To avoid conflicts when accessing card data later from your PC, offset 8 kilobytes from the beginning of the card (8 * 1024 = 8192 bytes or 16 blocks of 512 bytes, or 0x10 blocks in hexadecimal representation).

Example for 8MB:

mmc dev 0
mmc erase 0x10 0x4000

Example for a 16MB:

mmc dev 0
mmc erase 0x10 0x8000

Now you need to copy the contents of the firmware from the flash memory chip to the RAM of the camera. To do that, clear a section of RAM (0x800000 bytes for a 8MB chip or 0x1000000 bytes for a 16MB chip), read the flash memory and copy the entire contents to the prepared space in RAM. Then export the copied data from RAM to the card.

Example for 8MB:

mw.b ${baseaddr} ff ${flashsize}
sf probe 0
sf read ${baseaddr} 0x0 ${flashsize}

mmc write ${baseaddr} 0x10 0x4000

Another example, for 16MB:

mw.b ${baseaddr} ff ${flashsize}
sf probe 0
sf read ${baseaddr} 0x0 ${flashsize}

mmc write ${baseaddr} 0x10 0x8000

Remove the card from the camera and insert it into a computer running Linux. Use dd command to copy data from the card to a binary file on the computer.

Example for 8MB:

sudo dd bs=512 skip=16 count=16384 if=/dev/sdc of=./fulldump.bin

Example for 16MB:

sudo dd bs=512 skip=16 count=32768 if=/dev/sdc of=./fulldump.bin

Uploading binary image via serial connection.

There are cameras that only have wireless connection unavailable directly from bootloader. Most of such cameras also have SD card slot but some don't, or it does not work for some reason, or you don't have a card, or something. Anyway, you still can upload a binary image onto camera and either run it, or save it into the flash memory. Here's how.

First of all, you'll need to install lrzsz package on your desktop computer. I presume it runs Linux and preferrably of a Debian family, that'll be easier on examples. So, run this command to satisfy prerequisites:

apt install lrzsz

Now you are ready.

Place the binary file you are going to upload into the same directory where you will be starting a screen session to your camera from. Start the session and boot into the bootloader console interrupting booting routine with a key combo.

Now you can run help and check what data transfer protocols are supported by your version of bootloader. If you see loady in the list of commands, then you can use ymodem protocol. Run loady on you camera, then press Ctrl-a followed by : (semi-colon). It will switch you into command line at the very bottom of the screen.

Enter exec !! sz --ymodem filename.bin where filename.bin and see your file uploading via serial connection. At 115200 bps. Slow, very slow.

After the file is uploaded, you can do the usual magic. Either boot from the memory image right away using bootm, or write it into the flash memory.

Flashing full image via serial connection

Before you start, prepare the environment.

Download the full firmware binary for your SoC and flash chip from OpenIPC web site after submitting the settings form and clicking the link hidden under "Alternative method" button.

Open screen and connect to UART port.

screen /dev/ttyUSB0 115200

Sign in into bootloader shell and run:

mw.b ${baseaddr} 0xff ${flashsize}
loady ${baseaddr}

press "Ctrl-a" followed by ":", then type

exec !! sz --ymodem fullimage.bin

after the image is loaded, continue

sf probe 0
sf erase 0x0 ${flashsize}
sf write ${baseaddr} 0x0 ${filesize}

Flashing full image from TFTP

Before you start, prepare the environment.

Download full image binary for your SoC and place it in the root directory of your local TFTP server.

Start the session and boot into the bootloader console interrupting booting routine with a key combo. When in the console, set up parameters of your local network, if needed.

setenv ipaddr 192.168.1.10
setenv netmask 255.255.255.0
setenv gatewayip 192.168.1.1
setenv serverip 192.168.1.254

Use the following commands to re-flash your camera with the full image:

Example for 8MB:

mw.b ${baseaddr} 0xff ${flashsize}
tftpboot ${baseaddr} openipc-${soc}-lite-8mb.bin
sf probe 0; sf erase 0x0 ${flashsize}; sf write ${baseaddr} 0x0 ${filesize}
reset

Example for 16MB:

mw.b ${baseaddr} 0xff ${flashsize}
tftpboot ${baseaddr} openipc-${soc}-ultimate-16mb.bin
sf probe 0; sf erase 0x0 ${flashsize}; sf write ${baseaddr} 0x0 ${filesize}
reset

At the first boot, sign in into the bootloader shell once again and remap partitioning running run setnor16m command.

Reading binary image from SD card.

Before you start, prepare the environment.

If your camera supports SD card and you have fatload command in bootloader, then you can read firmware binary files from an SD card.

First, prepare the card: format it into FAT filesystem and place bootloader, kernel, and rootfs binary files there. Insert the card into camera and boot into bootloader console.

Check that you have access to the card.

mmc rescan

Then unlock access to flash memory and start writing content of the files from the card into the flash memory.

NB! Please note that load address and names of files used in this example not necessarily match those for your particular camera. Consult documentation, or seek help on our Telegram channel.

Flash bootloader.

mw.b ${baseaddr} 0xff 0x50000
sf probe 0
sf erase 0x0 0x50000
fatload mmc 0:1 ${baseaddr} u-boot-with-spl.bin
sf write ${baseaddr} 0x0 ${filesize}

Flash kernel.

mw.b ${baseaddr} 0xff 0x200000
sf probe 0
sf erase 0x50000 0x200000
fatload mmc 0:1 ${baseaddr} uImage.${soc}
sf write ${baseaddr} 0x50000 ${filesize}

Flash root filesystem.

mw.b ${baseaddr} 0xff 0x500000
sf probe 0
sf erase 0x250000 0x500000
fatload mmc 0:1 ${baseaddr} rootfs.squashfs.${soc}
sf write ${baseaddr} 0x250000 ${filesize}

Bypassing password-protected bootloader.

Changing the bootloader is a risky operation. There's a high probability of turning your camera into a paperweight if something goes wrong. So before you flash a new bootloader you have to weigh up all the risks and benefits. In most cases the original bootloader plus new kernel and new operating system should work just fine. But there are exceptions.

Shorting pins on flash chip

If you can't interrupt the boot sequence with a key combination, or if your camera requires a bootloader password that you don't know, you can still make it stop the Linux kernel booting and throw you into the shell.

The first thing to do is locate the flash memory chip on the camera circuit board. Typically this is a square chip with 8 pins labeled 25Q64 or 25Q128, rarely 25L64 or 25L128. If you have trouble locating the chip, try taking some pictures of your board from both sides. Then ask for help in our Telegram channel. Do not try to short-circuit any random chip! It will most likely burn your camera circuit.

Short-circuit pins 5 and 6 of the flash chip with a small metal object, a screwdriver or tweezers, right after the bootloader starts but before it calls up the Linux kernel.

Pins 5 and 6 of the SOIC8 chip are on the opposite corner of pin 1, indicated by the embossed or drawn dot next to it.

This hack in details

Downgrading stock firmware.

Today, we see more and more cameras where access to bootloader console is protected with a password. Thus, even if you connect to the camera's UART port, all you will see after interrupting the standard boot cycle is a prompt for password. In that case, a relatively safe solution is to downgrade the firmware to a version where the password protection was not yet implemented. For example, for Xiongmai cameras the bootloader password protection started popping up somewhere around July 2021, hence you need a firmware for your camera from an earlier date. After you successfully downgrade your camera to a password-free bootloader, you could install the OpenIPC firmware in a regular way.

Side-loading unlocked bootloader.

Many modern cameras utilize fastboot protocol that allows camera to load a bootloader binary code directly into memory and then run it from there. Check if our burn utility supports your camera's SoC.

Modifying stock firmware.

One way to bypass the bootloader protection is to dump original firmware and replace bootloader there with an unlocked alternative. Or you could flash the entire OpenIPC firmware since you have the chip in the programmer, anyway.

DO NOT FORGET TO MAKE A BACKUP OF YOUR ORIGINAL FIRMWARE!

Troubleshooting

Before you start, prepare the environment.

If you get Too many args error while trying to set an environment variable, try to do that from within Linux using fw_setenv instead of setenv in U-boot.

U-boot console:

hisilicon # setenv uk 'mw.b ${baseaddr} 0xff ${flashsize}; tftp ${baseaddr} uImage.${soc}; sf probe 0; sf erase 0x50000 0x200000; sf write ${baseaddr} 0x50000 ${filesize}'
** Too many args (max. 16) **

OpenIPC Linux:

root@openipc-hi3518ev100:~# fw_setenv uk 'mw.b ${baseaddr} 0xff ${flashsize}; tftp ${baseaddr} uImage.${soc}; sf probe 0; sf erase 0x50000 0x200000; sf write ${baseaddr} 0x50000 ${filesize}'