Quote:
Originally Posted by ChriChri
I need to take a break from looking into it, because I have to take care of other things (but I'll continue when time comes ;-) ).
To get into FEL mode I did the following:
- connected to my computer (linux) via usb
- pushed and hold power button (the one with the led) until device vanished from usb (reading dmesg) to make sure it is really switched off
- hold home button (the button all to the left below the display) and hit power button once to switch on
- in dmesg there should appear a different device (mine: idVendor=1f3a, idProduct=efe8, bcdDevice= 2.b3)
- FEL mode 
Recompiling my sunxi-tools with the patched source mentioned here got me - what looks for me - valid answers from the device.
I extracted boot0 eGON from my devices eMMC image and tried to upload it using sunxi-fel and got corresponding messages in the serial console of my test board.
I found out the sunxi-package format that is used for the .uboot-file contained in the firmware package by pocketbook. It contains sections for u-boot, soc-cfg oder dtb. I guess it could be possible to extract informations needed to build a u-boot from scratch. There is also information on the sunxi-wiki on how to get informations.
Then I got stuck - cause: lack of knowledge . Didn't know how to get a file containing SDL and uboot to upload to the device.
I decided to stop at this point and start again later with starting a device page for the board as proposed in the sunxi wiki. My hope would be to learn while doing so as much as I need to make a system boot via FEL/usb (hopefully with the help of the sunxi community). |
There are multiple issues with old sunxi-tools tutorials because the eGON format (version 4.0) has changed. The sunxi-package stuff is parsed by allwinner's modified uboot in lieu of its own classic dtb.
That makes going through that route a bit awkward. I've managed to fire this "native" uboot up by just burning it to memory via fel write/exec (turns out you don't need egon SPL on newer allwinners, as by the time you get to fel, DRAM is already configured, no more 32k sram limit).
Most crucially, it's possible to fire swupdate binary this way (and debrick your device if you seriously hose mmc0).