Difference between revisions of "Boot options 393"

Revision as of 17:21, 15 December 2016

Description

Normally camera boots from the internal NAND flash memory, and it is always possible to boot it from the micro SD card, so even corruption of files on the internal flash will not "brick" the system. There are no buttons or switches on the camera - it should be instructed to change the boot source. Always booting from micro SD is not practical - in that case it would not be possible to leave a non-bootable card (intended just for image/video storage) in the camera slot.

There are two ways to switch camera to the micro SD boot mode.

One requires camera to be connected to the host computer with the USB cable (micro USB socket under the network jack - marked "console" on the picture). There is an internal USB-to-serial converter in the camera (CP2103) that offers 4 additional GPIO signals in addition to just the serial connection. One of these signals selects the boot source (GPIO0 - 0 - MMC, 1 - NAND), another (GPIO3 - 0 reset, 1 - normal operation). Unfortunately GPIO control of the CP2103 is not in a mainline cp210x Linux driver so this functionality requires a modified version (see instructions below).

Another way to "tell" the camera to boot from the μSD card instead of the internal NAND flash is to use a mechanically modified card or card adapter (such cards are provided with the camera). Standard specifies two alternative ways for detection of the card presence - one is a mechanical switch (closed when the card is inserted), another is a pull-up resistor on a data line. Camera uses both signals at boot time to determine the boot source:

• Switch not closed, pull-up resistor not detected -> no card present, boot from the internal NAND flash
• Switch closed -> data (non-bootable) card present, boot from the internal NAND flash
• Switch not closed, pull-up resistor is detected -> bootable card present, boot from the MMC card

Fig.2 Recovery μSD card ('cut' corner) - forces the system board to boot from it

Boot instructions

Recovery micro SD card

Requirements:

• A modified card that doesn't lock the mechanical CD pin in the slot - it's done by carefully filing off the corner (see Fig.2) - most cards have circuitry there and get damaged. Use the one that came with the camera or order a new one.

Instructions:

• insert the card, power on

Regular micro SD card

Requirements:

• μUSB-to-USB cable
• Linux: compile cp210x driver

Instructions:

• Power on
• Connect camera to PC using μUSB-to-USB cable
• Reload the cp210x driver:
  • unplug the μUSB-to-USB cable
  • From the terminal, run:

 sudo rmmod cp210x                                                                                                                                                                                                                                                            
 sudo insmod cp210x.ko

• • plug the cable back (the driver will stay loaded until the PC is rebooted).

• From the terminal, run:

./cp210x_gpio.py 0x6;
./cp210x_gpio.py 0xe;