Xiaomi Mi 9 (xiaomi-cepheus)
|Original software||Android 9.0, up to 10, MIUI 11|
|Chipset||Qualcomm SM8150 Snapdragon 855|
|CPU||8-core (1x 2.84 GHz Kryo 485 & 3x 2.42 GHz Kryo 485 & 4x 1.78 GHz Kryo 485)|
|Display||1080 x 2340|
Users owning this device
How to enter flash mode
Like other Xiaomi devices, the user will have to acquire the bootloader unlock key: https://en.miui.com/unlock
The device will not unlock if the device isn't 7 days old (from the time when your device connects to internet and powered on, and linked with Mi Account)
- Turn the device off (or restart also works)
- Hold and button
- Once you feel vibration and phone turns on, release button
- Keep holding until you get to recovery.
Flashing (Download, Fastboot) mode
- Same as recovery, but this time hold the and keys.
Getting logs through debug UART
Tested! It works extremely well and the TX pin is easily accessible even without soldering.
For the ground you can force a breadboard pin into some metal shield. Be careful not to break the back being of a glassy material, so use a piece of plastic such as a credit card (not to scratch the metal edges) to unstick the glue in the edges. To get the credit card into the edges you must first heat them with a phono or with a gas stove and then with a suction cup lift the back (opposing the strength of the glue). Never bend the back too much to avoid the risk of breaking it, but it is relatively flexible and always keeping in mind that it is a glassy material you will not have to leave defects, let alone cracks. If you care about aesthetics and plan to combine a mess, I recommend you put a spare back on the cart, they have a paltry price. The image below indicates which are the serial pins, this is the upper board.