Hi Mazur ,
Android 8.1 doesn't support I.MX7ULP, starting from android 9.0.0_2.2.0,i.mx7ulp is supported by android.
As for user mode, described in android user's guide, see below, please!
The main differences among the three modes are as follows:
• eng (development configuration with additional debugging tools)
• Installs modules tagged with: eng and/or debug.
• Installs modules according to the product definition files, in addition to tagged modules.
• ro.secure=0
• ro.debuggable=1
• ro.kernel.android.checkjni=1
• adb is enabled by default.
• user (limited access, suitable for production)
• Installs modules tagged with user.
• Installs modules according to the product definition files, in addition to tagged modules.
• ro.secure=1
• ro.debuggable=0
• adb is disabled by default.
• userdebug (like user but with root access and debuggability, preferred for debugging)
• Installs modules tagged with debug.
• ro.debuggable=1
• adb is enabled by default.
So above 3 modes are all supported.
Have a nice day!
Weidong