Backup fsg, modemst1, modemst2, NON-HLOS.bin, persist.img, prog_emmc_firehose_8916.mbn and sec.dat from MIUI ROM 8.5.7.0 Global Stable. You can use all files to repair Xiaomi Redmi 4A (Rolex) with no signal, invalid IMEI, wifi, baseband unknown, and MAC address.
Restore all files according to the partition using the UFI Android ToolBox or other Qualcomm Flash Tool.
Scanning for Qualcomm HS-USB QDLoader 9008 device...
Download Port: Qualcomm HS-USB QDLoader 9008 (COM15)
USB Driver: [Qualcomm Incorporated] qcusbser, version: 2.1.2.0, date: 7-8-2015
Initializing... Done.
platform: msm8937, cpu abi: arm64-v8a
manufacturer: Xiaomi
board: QC_Reference_Phone, name: rolex
brand: Xiaomi, model: Redmi 4A
build id: MMB29M, version: 6.0.1 Marshmallow (MMB29M) (MIUI8)
build description: rolex-user 6.0.1 MMB29M V8.5.7.0.MCCMIED release-keys
Reading modem at 0x04000000-0x093FFFFF size: 84 MiB... Done.
Reading modemst1 at 0x0D682400-0x0D8023FF size: 1.50 MiB... Done.
Reading modemst2 at 0x0D802400-0x0D9823FF size: 1.50 MiB... Done.
Reading fsg at 0x10008000-0x10187FFF size: 1.50 MiB... Done.
Reading sec at 0x10188000-0x1018BFFF size: 16 KiB... Done.
Reading persist at 0xF4000000-0xF5FFFFFF size: 32 MiB... Done.
Reading config at 0xF6180000-0xF6187FFF size: 32 KiB... Done.
Download backup_modem_rolex-user_6.0.1_MMB29M_V8.5.7.0.MCCMIED_release-keys_SmartPhones.How