Samsung has apologized and offered refunds to customers of its ill-fated Galaxy Note 7, but a new report comes the closest to doing something that the Korean tech giant hasn't so far: explaining why the Note 7s began overheating and exploding in the first place.
The report, published on Friday by quality assurance firm Instrumental, suggests that design flaws, not the Note 7's battery, are to blame. In a blog post, Instrumental engineers described that they found "intellectual tension between safety and pushing the boundaries" in a recent teardown of a Note 7.
The teardown revealed that the Note 7 has so little space between the battery and the rest of its components that slight pressure, such as sitting on the phone while it's in a back pocket, could cause the the polymer separator layers that keep the battery safe to come in contact with one another.
Instrumental found that the battery is contained in a thin shield, suggesting that Samsung was trying to mitigate the effects of pressure. But enough pressure could squeeze the separators to a point where the positive and negative layers would touch and cause the battery to explode.
"Looking at the design, Samsung engineers were clearly trying to balance the risk of a super-aggressive manufacturing process to maximize capacity, while attempting to protect it internally," the Instrumental engineers wrote.
Samsung has offered no definitive explanation for the Note 7 woes. It last issued a statement in early November, when it said that approximately 85 percent of all recalled Note 7 devices had been replaced. In an attempt to collect the remaining ones, the company released a software update that prohibits the battery from being charged to more than 60 percent capacity and issues pop-up reminders to owners that their phones are eligible for refunds or replacements.
This article originally appeared on PCMag.com.