Why would You thinking overwriting each sector is impossible on dying HDD? Bad sector means magnetically unstable area, which means all data written there (i.e 512 bytes) can be easily changed by other factors than strong magnetic field by head as normally should.
Maximum write speed for Your device multiplicate by
You will not know if there is or not issue with HDD if not check S.M.A.R.T report from at least short test...
For such task, first You must solve the error number issue. You have said that You formatted HDD, so this for sure eliminating damaged FAT32 partition when update package is copying during updating firmware process.
If HDD report return fine values, then maybe You didn't patched firmware to be able to install CFW? Are You using bgtoolbox? You should because it easy and brick proof.
I followed the Mr Mario YT tutorial step by step, unless maybe I missed a step. Im pretty sure this is the bgtoolbox method. I will go back over my steps.
Thank you
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