Download Sony Xperia XA1 Ultra (Dual Sim) official firmware from the link here, and follow the provided flashing instructions to learn how to flash the stock rom.
If you notice that any of the links provided below is broken or doesn’t work, please post in comments section so we fix and update it ASAP.
Download Options
File Name: XA1_Ultra_Dual_G3212_7.0_42.0.A.1.54_ServiceExchangeUnit.ftf
Size: 2 GB
Android version: 7.0
Firmware – Download
File Name: XA1_Ultra_Dual_G3212_7.0_42.0.A.1.69_CentralEurope1.ftf
Size: 2 GB
Android version: 7.0
Firmware – Download
File Name: XA1_Ultra_Dual_G3212_7.0_42.0.A.1.90_CommonwealthOfIndependentStates.ftf
Size: 2 GB
Android version: 7.0
Firmware – Download
File Name: XA1_Ultra_Dual_G3212_7.0_42.0.A.3.30_CentralEurope1.ftf
Size: 2 GB
Android version: 7.0
Firmware – Download
File Name: XA1_Ultra_Dual_G3212_7.0_42.0.A.4.101_CommonwealthOfIndependentStates.ftf.ftf
Size: 2 GB
Android version: 7.0
Firmware – Download
File Name: XA1_Ultra_Dual_G3212_7.0_42.0.A.4.89_CommonwealthOfIndependentStates.ftf
Size: 2 GB
Android version: 7.0
Firmware – Download
How to flash
After downloading any of the above firmware, follow the instructions here to flash.