USB BOOT mode

In order to reflash your NanoNote with the xburst tools (usbboot), you have to boot the device in USB BOOT mode.

Software USB_BOOT

Hold the [U] key while powering on the NanoNote ([POWER] + [U]) to enter software usbboot mode. Note, the device screen will not power on in USB BOOT mode.

Note to anyone who wants to write a kernel which should be bootable through here: to indicate that this is software boot mode, meaning that the sdram is already initialized, u-boot writes 0xff to the byte at offset 20 from the entry point address when running stage 1. Also, it will not flush the entire caches, but only from the entry point. So your entry point must be the first byte of your stage1 file, and the fifth word (at byte 20) must be set to 0 (and not executed). You can read it back and skip the sdram setup if it has been changed.

Hardware USB_BOOT

The NanoNote board has two pins you have to short. The following is guide step by step to get this mode running:

Basically, NanoNote enters boot mode, when it's booted up while the USB Boot pins are shortened and the USB cable is connected to a computer.

1. Take the battery out.
2. Connect the NanoNote to your computer with a USB cable: Sometimes when you connect the USB cable (without a battery in the device), the device will turn on by itself, even without the power button being pressed. If that happens, just unplug and replug the USB cable until it remains off.
3. Make sure usbfs is mounted on /proc/bus/usb and run watch lsusb in a terminal.
4. This is the key point: Turn the device around and the carbonized rubber button to short the two pins that show through the hole in the label affixed underneath the battery. Make sure the pins are clean (e.g. grease or dust could prevent shorting).

USB Boot pins

Carbonized rubber button

1. Press the power button for about 2 seconds while maintaining the USB Boot pins shortened.
2. The device should remain dark (LCM black). If it remains dark (and you pressed the power button long enough), you are now most likely in USB boot mode. If the LCM turns on, you did not successfully short the 2 pins.
3. The watch lsusb output will now show a line with 601a:4740. In the kernel log (dmesg) you will get something like this: (on some systems, like *buntu, you might see only the first two lines)

usb 1-5: new high speed USB device using ehci_hcd and address 6
usb 1-5: configuration #1 chosen from 1 choice
usb 1-5: New USB device found, idVendor=601a, idProduct=4740
usb 1-5: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-5: Product: JZ4740 USB Boot Device
usb 1-5: Manufacturer: Ingenic

4. Make sure /dev/bus/usb points to a usbfs file system. For example, /dev/bus/usb may be an empty directory on which you mount usbfs

 $ mkdir -p /dev/bus/usb
 $ mount -t usbfs none /dev/bus/usb

Or /dev/bus/usb may be a symbolic link to /proc/bus/usb on which you may mount usbfs.

5. Run the usbboot application on your computer, either directly or through the reflash_ben.sh script. If it says

 Error - no XBurst device found

then you are not in USB_BOOT. Try again.

If it says

 Now checking whether all configure args valid: YES
 Current device information:
 CPU type is Ingenic XBurst Jz4740

then you are in USB_BOOT mode and reflashing should take place

one more item: it takes some time for the ben to discharge. remove battery, disconnect usb, wait 30 seconds (!), short the usb boot pins (and keep them shorted), connect usb, wait a couple of seconds, then release the usb boot pins.

Not sure if this is still true:

There is a little red LED on the right side. You can only see it if it's dark. If you plug in the USB cable, there is a brief moment when it's very bright. Then it goes into 'half bright' state. When you boot the device (either via flash or USB), it will go to a very low bright state, almost dark. That's another way how you can see whether you have booted into USB boot mode. If you short the two USB boot pins, then press the power button and then you can see how the LED goes dark (and the LCM stays dark as well), then you are in USB boot state. --MichaelShiloh 04:44, 14 September 2009 (UTC)

Check if you are in USB Boot Mode

Use lsusb on your host PC and if you see this line 601a:4740 you are in USB Boot mode.

Reboot the NanoNote

Once you're done and are ready to reboot the machine, unplug the USB cable. If this doesn't work, use the hardware reset on the bottom of the device.