hello andrew.fernandes,
to clarify…
you don’t need to fuse the target (i.e. PKC, SBK) to enable disk encryption.
LUKS disk encryption support with a specific key. you should execute the script file, gen_ekb.py to generate an image. also, in the developer guide, [Tool for EKB Generation] that sym2.key is equivalent to ekb.key
please see-also Topic 270934, we’ve also check disk encryption with a custom key, it has worked normally with non-fused target.
as for WARNING: Test Key is used. message,
it’s reported by UEFI. you may refer to the public sources,
for example, edk2/MdeModulePkg/Universal/BdsDxe/BdsEntry.c at master · tianocore/edk2 · GitHub
this is normal message since the [UEFI Secureboot] has not enabled.