I have a customer who submitted a ST500LM000 that had stuck heads. After head swap, was able to image around 25% of the drive and then it quit responding. I think that there is a problem with the onboard cache and would like to swap PCBs w/ ROM transfer to test. My question is, does running IO from terminal on the donor drive accomplish the same thing as performing a secure erase? It seems both methods work to clear the cache, but wanted to get everyone's input.

Issuing I from level O will erase flash and init ALF tables, so its not the same as secure erase.
When you say quit responding what do you mean? You did a head swap, so if heads where bad in the beginning i would look there again, terminal should also give you some hints.
To change PCBs on these you might need to adapt donor ROM, use ACE labs solution or disable NAND.

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