Hoping below information will help you.
Firmware Update Steps:
Check your current HW and SW version with the following string: *#4986*2650468#
To set download mode on your device, you have to press Volume DOWN + Camera Key and Power Button.
Run S8530 Wave II downloader.
Select LSI
Tick Boot Change and and Tick Full Download
Click Boot and select Boot folder: (named as BOOTFILES)
Click AMSS and select : amss.bin
Click Apps and select : apps_compressed.bin
Click Rsrc1 and select : Rsrc_S8530_Open_Europe_Common.rc1
Click Rsrc2 and select : Rsrc2_S8530_Open_Euro_Common (Low/Mid).rc2
Click Factory FS and select : FactoryFs_S8530_Open_Europe_Common.ffs
Click CSC and select : S8530XXXXX.csc
Click SHP APP and select : ShpApp.app
Click FOTA and select : bplib_S8530OpEuroCommon.fota
After connecting the mobile with PC, Multiloader should find the COM port automatically. If it cannot find COM port please connect USB cable again and press port search.
Click Download [You will see the downloading progress bar].
After finishing downloading, the mobile will be starting automatically.