Some hints about diagnose mode

The data is from https://forum.xda-developers.com/general/help/idea-to-root-sonys-e-reader-dpt-rp1-t3654725/page8

Thanks the author - shankerzhiwu

About the OTG cable, I have no shortcut available. Pinout of micro usb plugs can be found on https://en.wikipedia.org/wiki/USB_(Physical)#Pinouts . The 7.87 k resistor should be soldered between ID(PIN 4) and GND(PIN 5). Alternately, you can also use a 7.5k resistor. Since such resistor value is beyond OTG standard, you have to do the solder work. For simplicity, a breakout board can be used like http://www.digikey.com/product-detai...192-ND/5673778 . Moreover, you can also choose to only solder the resistor itself without a USB cable. If so, after the gray rect is shown on the screen, the OTG plug can be safely disconnected and a normal USB to micro USB cable can be used to connect the DPT to your computer.

The detailed steps for entering diagnose mode are :

1. Power off your DPT.
2. Connect the OTG cable.
2. Press and hold the Home button.
3. With the Home button pressed, press and release the Power button.
4. Continue holding the Home button. See if anything is shown on the screen.
4.a. If "Welcome" screen shows, which means that the Home button is not detected pressed when booting, go back to step 1.
4.b. If nothing is shown on the screen and the power LED is also not flashing, which means that you are too nervous to trigger the power button -- your DPT is not powered on at all, go back to step 3.
4.c. if nothing is shown on the screen and the power LED keeps flashing, then the Home button can be released.
5. Wait for about 12 seconds. See if anything is shown on the screen.
5.a. If the screen flashes blank and the power LED stops flashing and turns off, which means that the id resistor is not soldered well (ill-connected or wrong value)., check your OTG cable and go back to step 2.
5.b. if a gray rect is shown on the screen, the device is now in diagnose mode
6. If a USB cable is not soldered with the micro USB plug, you can now unplug it and use a normal micro USB cable to connect the DPT with your computer.
7. A USB modem device should now be detected on the computer. Use a serial terminal software to access the diagnose tty.