Hello, i bought a My Cloud Home Duo, and as soon i started using it, i realize that it was a good deal because the disks inside, but the system for me is terrible, so I know the Home of one disk can be modded to use Open Media Vault, and I started experimenting with the Home Duo, I manage to create a bootable usb, (with some conditions) Clean OS (Debian), OpenMediaVault and other "firmwares" , and find a way to extract the firmware (and break it), so as impatient as I am, i not only manage to brick the device, a manage to write the banana pi w2 bootloader, and brick it even more :D. So in case that someone is playing with this board and break it, i´m gonna tell my experience:
IMPORTANT!!!: I am not developer, engineer, or know something about embedded system, i´m just a median user of linux, and for better or worst i don’t mind if i break this device, i don´t know what i´m doing, but i was lucky recovering the device, this instructions must be followed only in the worst case scenario and i´m not responsible of anything that can happen to your board, you been warned.
First, you need to disassembled the device, there is 4 screws on the bottom (1 on every foot), and then you have 3 tabs on every side, and one on the rear, (totalling 7 tabs) you can only access every one separated whit one piece of thin plastic of 2cm approximately of thickness, because there are 10 total plastic sticks protecting the tabs you cannot slide a plastic card, there you have some fotos so you can understand better, this photos are all from the grey part, you must introduce the plastic from top to bottom, there’s not tab on the front (where is the light): https://justpaste.it/2utnb
After that you need to connect to UART port, luckily is very easy, remember to connect Tx to Rx, Rx to Tx and GRND to GRND, NEVER connect vcc. After you connected with UART, you can open a terminal (hyperterminal, putty, minicom, etc.) and press ctrl + q and then turn on the device, if you see on the terminal “d/g/r>” well good news, your device is not dead. (control +q is only to check that the board is alive, we don´t gonna use it, because realtek has an app that makes everything automatic)
So now you need your board connected to UART and turned off, we´re gonna use the kylin_bootcode_recovery_tool that you can download from here: https://mega.nz/folder/04hDQJwD#Ez4CHKs6UXvqYaU4pYwKdg it include the files for the Home Cloud DUO, i compiled myself, and if you want to compile as in the sources, it tries to write to SPI, so I change a lot of files modifying SPI to EMMC (as I said earlier, i don’t know what i’m doing, i´m not a developer, so be careful), you open the recovery tool, load the config file on the first line and the bin file on the second, and push write (LK option must be NOT checked), then you turn on your board, after it says success, congratulations, now you can boot from recovery as always, with reset button and a usb (remember that with my files you also need the 2 disks inserted, i still not found a way of booting without disks), and with DD command you can restore your eMMC dump, or make the changes you need. Hope this is useful.
Thanks to godex from 4pda, who like me is trying to bring OMV to this device, and to Danman whose blog was very useful https://blog.danman.eu/zidoo-x8-recovery/