Mocha bricked

[Vin100]

I've tried to install a better rom on Mipad1 (mocha) by following [GUIDE][HOW TO]Flash TWRP And Merge Partitions on Mi Pad 1 (Mocha)
But it bricked the system, fortunately MultiROM TWRP (v2.8.4) is installed.
I've tried to reinstall a global stable rom

• By fastboot flashall (mocha_global_images_V7.5.2.0.KXFMIDE_20160712.0000.26_4.4_global_da3d0b8d81) but I got always errors like ANDROID_PRODUCT_OUT not set
• By adb push to root ( miui_MIPADGlobal_V7.3.1.0.KXFMIDD_0d8dcf2bc3_4.4) and then tried to install with TWRP but I always got some problems (impossible to mount/wipe cache, etc...)

Finally I could install by adb push in /sdcard & install with TWRP And it's working
But a working system installed on broken system is not a solution.
System is mountpoint /system - ext4 - Cache is mountpoint /cache - ext4 - Data is mountpoint /data - ext4
Are my partition merged ? How to fix all that
Could someone give me a link for a clean install
Thanks