I have the same problem, the A260F phone is Hard lock by Operator cannot flash any Combination or Any Official Firmware.
8/4/2020 10:19:21 PM> Looking for EasyJTAG box...
8/4/2020 10:19:21 PM> EasyJTAG API ver. 3401
8/4/2020 10:19:22 PM> OpenUSB returned = 0
8/4/2020 10:19:22 PM> EasyJTAG Box Serial = F6F272D292237F2E
8/4/2020 10:19:24 PM> Card Serial = AA2778BA
8/4/2020 10:19:24 PM> EasyJTAG Box Firmware = 2.5204
8/4/2020 10:19:24 PM>
8/4/2020 10:32:48 PM> Looking for EasyJTAG box...
8/4/2020 10:32:48 PM> EasyJTAG API ver. 3401
8/4/2020 10:32:48 PM> Setting IO Levels to 1.8V
8/4/2020 10:32:48 PM> Setting frequence to 1 MHz
8/4/2020 10:32:48 PM> EasyJTAG Box Serial = F6F272D292237F2E
8/4/2020 10:32:48 PM> EasyJTAG Box Firmware = 2.5204
8/4/2020 10:32:49 PM> Setting interface to EasyJtag2/ISP
8/4/2020 10:32:50 PM> Setting bus width to 1 Bit
8/4/2020 10:32:50 PM> Setting frequence to 1 MHz
8/4/2020 10:32:50 PM> CMD Pullup Level: 466 mV
8/4/2020 10:32:50 PM> CMD Active Level: 1201 mV
8/4/2020 10:32:50 PM> eMMC Init returned = 0
8/4/2020 10:32:50 PM> EMMC Device Information :
8/4/2020 10:32:50 PM> EMMC CID: 150100384754463452004DBDFAAEC6EB
8/4/2020 10:32:50 PM> EMMC CSD: D02701320F5903FFF6DBFFEF8E40400D
8/4/2020 10:32:50 PM> EMMC Manufacture : SAMSUNG , EMMC NAME: 8GTF4R , HEX: 384754463452 , S/N: 4DBDFAAE , rev. 0x00
8/4/2020 10:32:50 PM> EMMC Manufacture ID: 0x15 , OEM ID: 0x00 , Device Type: BGA (Discrete embedded) , Date: 12/2019
8/4/2020 10:32:50 PM> EMMC ROM 1 (Main User Data) Capacity: 7456 MB (0001D2000000)
8/4/2020 10:32:50 PM> EMMC ROM 2/3 (Boot Partition 1/2) Capacity: 4096 KB (000000400000)
8/4/2020 10:32:50 PM> EMMC RPMB (Replay Protected Memory Block) Capacity: 4096 KB (000000400000) Counter: 2 , Response: Not Clean
8/4/2020 10:32:50 PM> EMMC Permanent Write Protection: No
8/4/2020 10:32:50 PM> EMMC Temporary Write Protection: No
8/4/2020 10:32:50 PM> Extended CSD Information :
8/4/2020 10:32:50 PM> Extended CSD rev: 1.8 (MMC 5.1)
8/4/2020 10:32:50 PM> Boot configuration [PARTITION_CONFIG]: 0x48 , Boot from: ROM2 (Boot partition 1)
8/4/2020 10:32:50 PM> Boot Bus Config: 0x01 , width 4bit
8/4/2020 10:32:50 PM> H/W Reset Function [RST_N_FUNCTION]: 0x00, RST_n signal is temporarily disabled
8/4/2020 10:32:50 PM> Supported partition features [PARTITIONING_SUPPORT]: 0x07
8/4/2020 10:32:50 PM> Device supports partitioning features
8/4/2020 10:32:50 PM> Device can have enhanced technological features in partitions and user data area
8/4/2020 10:32:50 PM> Device can have extended partitions attribute
8/4/2020 10:32:50 PM> Partition Settings [PARTITION_SETTING_COMPLETED]: 0x00
8/4/2020 10:32:50 PM> Backup saved: 8GTF4R_4DBDFAAE_20200804_223250.extcsd
8/4/2020 10:32:50 PM> EMMC Init completed.
8/4/2020 10:32:50 PM>
8/4/2020 10:32:50 PM> Operation: Find table from emmc
8/4/2020 10:32:50 PM>
8/4/2020 10:32:50 PM> Vendor: Samsung
8/4/2020 10:32:50 PM> Searching GPT ...
8/4/2020 10:32:50 PM> GPT header is found and is valid
8/4/2020 10:32:50 PM> Checking for ROM2 ...
8/4/2020 10:33:01 PM> Error reading at address: 000000000000 , error: -3, DATA RCV Timeout Error ... Retry #1
8/4/2020 10:33:01 PM> Error result: -3
8/4/2020 10:33:02 PM> ROM2 is not blank
8/4/2020 10:33:02 PM> Checking for ROM3 ...
8/4/2020 10:33:13 PM> Error reading at address: 000000000000 , error: -3, DATA RCV Timeout Error ... Retry #1
8/4/2020 10:33:13 PM> Error result: -3
8/4/2020 10:33:14 PM> ROM3 is not blank
8/4/2020 10:33:14 PM> GPT header successfully parsed
8/4/2020 10:33:14 PM>
8/4/2020 10:33:14 PM> EFS backup is performed. Please wait...
8/4/2020 10:34:31 PM> Setting IO Levels to 1.8V
8/4/2020 10:34:33 PM>
8/4/2020 10:34:33 PM> Too many errors. Enabling ResetBox mode
8/4/2020 10:34:33 PM>
8/4/2020 10:34:44 PM> Exception: read_dir/ext_dir_open: [system/]
8/4/2020 10:34:55 PM> Exception: read_dir/get_inode: [efs/recovery]
8/4/2020 10:35:06 PM> Exception: read_dir/get_inode: [efs/FactoryApp/batt_after_manufactured]
8/4/2020 10:35:17 PM> Exception: read_dir/ext_dir_open: [system/]
8/4/2020 10:35:28 PM> Error reading at address: 000000C00000 , error: -3, DATA RCV Timeout Error ... Retry #1
8/4/2020 10:35:28 PM> Error result: -3
8/4/2020 10:35:39 PM> Error reading at address: 000000C00000 , error: -3, DATA RCV Timeout Error ... Retry #2
8/4/2020 10:35:39 PM> Error result: -3
8/4/2020 10:35:50 PM> Error reading at address: 000000C00000 , error: -3, DATA RCV Timeout Error ... Retry #3
8/4/2020 10:35:50 PM> Error result: -3
8/4/2020 10:36:02 PM> Too many errors. Reading has been stopped
8/4/2020 10:36:02 PM> Try the "Skip unreadable blocks" option
8/4/2020 10:36:02 PM>