[Xiaomi Mi Mix 2S Guides, News, & Discussion] Saiger:
Here is the link for the closed beta rom of miui based of android 9.

If you want to use the china/gloabl rom use this debloat tool to remove unwanted apps/ads https://github.com/Saki-EU/XiaomiADBFastbootTools

Keep in mind that when you flash back to oreo your camera might stop working and you have to fastboot flash the global stable rom.

How to install by [MENTION=2313885]zipfelQ[/MENTION] - Thanks!

Because it helped me much to read the tricks on this Thread, i'll explain my Way to get successfully

FROM MIUI 8.8.4 Android 8.0 Global on XE TO MIUI 8.8.28 Android 9 - PI - Global

without any Data Loss and Magisk v17 afterwards (safetynet ok)

Installing PI

1. Download on PC latest Custom TWRP (v8 in the Moment) - https://xdaforums.com/xia...ix-2s-t3790922

2. Download on PC latest Magisk (v17 in the Moment) - https://github.com/topjohnwu/Magisk/releases

3. Download on Phone latest MagiskManager (v5.9.0 in the Moment) - https://github.com/topjohnwu/Magisk/releases

4. Download on Phone latest Global Miui10 Android9 Beta - https://xdaforums.com/xia...9-pie-t3826402

5. Put 1. and 2. in ADB Folder

6. On PC: adb reboot bootloader ENTER

7. ON PC: fastboot boot recovery-v8.img ENTER

8. Phone boots in TWRP - Enter Password to decrypt

9. On Phone in TWRP: Install 4. (latest PI zip) - "Dirty Flash" - Wipe Dalvic and Cache (no data loss)

10. On Phone in TWRP: Reboot -> System -> be happy

Installing Magisk v17

11. On PC: adb reboot bootloader ENTER

12. On PC: fastboot boot recovery-v8.img ENTER

13. On Phone in TWRP: Mount -> System

14. On Phone in TWRP: Advanced -> Sideload

15. On PC: adb sideload Magisk-v17.0.zip ENTER

16. On PC: adb shell ENTER cd system ENTER vi build.prop ENTER "Change ro.product.name" in "popolaris" (not polaris) ESCAPE :wq ENTER

17. On Phone in TWRP: Reboot -> System

18. Install on Phone 3. (MagiskManager apk) to have MagiskManager

19. Install Modules and be even more happy

Have Fun

China Closed Beta

http://bigota.d.miui.com/8.8.7/miui_MIMIX2S_8.8.7_1593b78a0e_9.0.zip 8.8.7

http://bigota.d.miui.com/8.8.8/miui_MIMIX2S_8.8.8_303fd2c80e_9.0.zip 8.8.8

http://bigota.d.miui.com/8.8.9/miui_MIMIX2S_8.8.9_3b344a8afe_9.0.zip 8.8.9

http://bigota.d.miui.com/8.8.10/miui_MIMIX2S_8.8.10_22c92b6efe_9.0.zip 8.8.10

http://bigota.d.miui.com/8.8.13/miui_MIMIX2S_8.8.13_7cefa564eb_9.0.zip 8.8.13

http://bigota.d.miui.com/8.8.15/miui_MIMIX2S_8.8.15_0fc7b72ccc_9.0.zip 8.8.15

http://bigota.d.miui.com/8.8.16/miui_MIMIX2S_8.8.16_f50f148a4e_9.0.zip 8.8.16

http://bigota.d.miui.com/8.8.29/miui_MIMIX2S_8.8.29_6a13b9ffa4_9.0.zip 8.8.29

http://bigota.d.miui.com/8.8.30/miui_MIMIX2S_8.8.30_aaca7a70f4_9.0.zip 8.8.30

http://bigota.d.miui.com/8.8.31/miui_MIMIX2S_8.8.31_d0859b7cdb_9.0.zip 8.8.31

http://bigota.d.miui.com/8.9.3/miui_MIMIX2S_8.9.3_ac7d80d717_9.0.zip 8.9.3

http://bigota.d.miui.com/8.9.4/miui_MIMIX2S_8.9.4_4ec7683b31_9.0.zip 8.9.4

http://bigota.d.miui.com/8.9.5/miui_MIMIX2S_8.9.5_1bba504e6f_9.0.zip 8.9.5

http://bigota.d.miui.com/8.9.6/miui_MIMIX2S_8.9.6_c615ab7bc9_9.0.zip 8.9.6

http://bigota.d.miui.com/8.9.11/miui_MIMIX2S_8.9.11_6c346a5d92_9.0.zip 8.9.11

http://bigota.d.miui.com/8.9.12/miui_MIMIX2S_8.9.12_df1c46e4e9_9.0.zip 8.9.12

http://bigota.d.miui.com/8.9.13/miui_MIMIX2S_8.9.13_df89b2e534_9.0.zip 8.9.13

http://bigota.d.miui.com/8.9.17/miui_MIMIX2S_8.9.17_3855c1f774_9.0.zip 8.9.17

http://bigota.d.miui.com/8.9.20/miui_MIMIX2S_8.9.20_be2f1f2e26_9.0.zip 8.9.20

http://bigota.d.miui.com/8.9.26/miui_MIMIX2S_8.9.26_7d8202a249_9.0.zip 8.9.26

http://bigota.d.miui.com/8.9.27/miui_MIMIX2S_8.9.27_fa5df41ac8_9.0.zip 8.9.27

http://bigota.d.miui.com/8.10.8/miui_MIMIX2S_8.10.8_d355863471_9.0.zip 8.10.8

Global Closed Beta

http://bigota.d.miui.com/8.8.7/miui_MIMIX2SGlobal_8.8.7_71ff63391b_9.0.zip 8.8.7

http://bigota.d.miui.com/8.8.16/miui_MIMIX2SGlobal_8.8.16_50fc174388_9.0.zip 8.8.16

http://bigota.d.miui.com/8.8.28/miui_MIMIX2SGlobal_8.8.28_0f28e75344_9.0.zip 8.8.28

http://bigota.d.miui.com/8.9.4/miui_MIMIX2SGlobal_8.9.4_f41f7411cf_9.0.zip 8.9.4

http://bigota.d.miui.com/8.9.11/miui_MIMIX2SGlobal_8.9.11_c7defa876b_9.0.zip 8.9.11

Global Open Beta

http://bigota.d.miui.com/8.9.7/miui_MIMIX2SGlobal_8.9.7_3f1fdd8006_9.0.zip 8.9.7

http://bigota.d.miui.com/8.9.13/miui_MIMIX2SGlobal_8.9.13_4590eb1e00_9.0.zip 8.9.13

http://bigota.d.miui.com/8.9.20/miui_MIMIX2SGlobal_8.9.20_8f2e175c08_9.0.zip 8.9.20