This is the common tree for ZTE Blade A1 (C880U and C880A).

• MT6735
• 2GB RAM / 16GB internal storage

Working:

• Backlight
• Audio
• WiFi
• Bluetooth
• Camera
• Sensors (seems only accelerometer is present on this model)
• GSM/WCDMA voice calls
• CDMA and GSM SMS

Mostly working:

• CDMA 3G data connectivity
  • Initial attach APNs are set correctly for both CDMA and GSM subscriptions
  • Attaching works at first boot
  • But not working anymore after toggling data switch

Not working but TODO:

• CDMA voice calls
• SVLTE data connectivity
• SIM switching
• VoLTE; this one is huge amount of work, hence priority is lower.

Mostly out of reach if not outright impossible:

• Fingerprint