Error L6002U showed this in the Build log:
linking....\Objects\WS_Passport_BL.axf: error: L6002U: Could not open file ..\..\..\..\..\..\..\..\..\..\AppData\Local\Arm\Packs_538\Keil\MDK-Middleware\7.16.0\Network\Lib\ARM\Net4_Dbg_CM3_L.lib: No such file or directory
I had checked the above relative path, it is correct, but the Linker couldn't see it.
I tried moving the current project folder to its parent directory, rebuild and it worked again!
So, my assumption is the package which has "long" relative path might cause this linker error.
Btw, these are some additional information about Middleware pack and Compiler toolchain:
Package Vendor: Keil
Middleware for Keil MDK-Professional and MDK-Plus
* Component: CORE Variant: IPv4 Debug Version: 7.18.0
* Component: ETH Version: 7.18.0
* Component: Legacy API Version: 7.18.0
* Component: Web Server Compact Variant: HTTP Version: 7.18.0
* Component: BSD Version: 7.18.0
* Component: TCP Version: 7.18.0
* Component: UDP Version: 7.18.0IDE-Version:µVision V126.96.36.199Copyright (C) 2022 ARM Ltd and ARM Germany GmbH. All rights reserved.Tool Version Numbers:Toolchain: MDK Plus 5.38 (Flex): 1 user(s) Version: 188.8.131.52Toolchain Path: C:\Keil_v538\ARM\ARMCC_506U7\BinC Compiler: Armcc.exe V5.06 update 7 (build 960)Assembler: Armasm.exe V5.06 update 7 (build 960)Linker/Locator: ArmLink.exe V5.06 update 7 (build 960)Library Manager: ArmAr.exe V5.06 update 7 (build 960)Hex Converter: FromElf.exe V5.06 update 7 (build 960)CPU DLL: SARMCM3.DLL V184.108.40.206Dialog DLL: TCM.DLL V220.127.116.11Target DLL: UL2CM3.DLL V18.104.22.168Dialog DLL: TCM.DLL V22.214.171.124