Proposed jury instruction. Click to view full order.

FORTUNE — The text at right is what Judge Judy Koh was prepared to tell the jury about Samsung’s policy of automatically deleting e-mails that might have been relevant to its patent battle with Apple AAPL .

Samsung objected. It insisted that Apple was equally guilty of evidence “spoliation.” As proof, it pointed out that the record contained no e-mails from Steve Jobs that mentioned the patent trial in the period between 2010 (when Apple sued Samsung) and Jobs’ death in 2011

Judge Koh seems to have been persuaded. FOSS Patents‘ Florian Mueller notes that late Sunday she filed an order that reversed a magistrate’s judge’s ruling and replaced the long instruction above with a pair of instructions that hold the two companies equally to blame. Unless Apple can change the judge’s mind on Monday, she will tell the jury:

“Samsung Electronics Company has failed to preserve evidence for Apple’s use in this litigation after Samsung Electronics Company’s duty to preserve arose. Whether this fact is important to you in reaching a verdict in this case is for you to decide.”

And the same thing about Apple:

“Apple has failed to preserve evidence for Samsung’s use in this litigation after Apple’s duty to preserve arose. Whether this fact is important to you in reaching a verdict in this case is for you to decide.”

Mueller describes the new instructions as a “major breakthrough” for Samsung. “This reversal,” he writes, “significantly increases the Korean company’s chances of getting a verdict it can live with.”