Samsung says bad batteries and rushed manufacturing doomed the Galaxy Note 7

Samsung has finally released the results of the inquiry it commissioned into exactly what went wrong with the Galaxy Note 7, an acclaimed smartphone that had to be pulled from the market entirely last year after widespread reports of fires caused by the device.

The company says there were two separate flaws with the Galaxy Note 7’s batteries. The first battery had a design flaw in the upper right corner that could cause a short circuit, according to Recode, while the second battery — used for replacement units — had a manufacturing issue that could lead to fires because of a welding defect. Some units of the second battery were also missing insulation tape.

Samsung conducted an investigation with 700 dedicated staff testing 200,000 phones and 30,000 extra batteries, also commissioning three outside firms — UL, Exponent and TUV Rheinland — that ended up finding similar results.

Last week The Wall Street Journal reported that the initial batch of issues was caused by an irregularly sized battery from Samsung’s own battery subsidiary, Samsung SDI. The subsequent ramp-up in production caused issues with replacement phones said to be carrying batteries from Amperex Technology.

Recode’s interviews with Samsung officials corroborate this information. “We believe if not for that manufacturing issue on the ramp (of Battery B), the Note 7 would still be in the market,” Samsung’s US head Tim Baxter says.

Earlier this month Samsung Electronics issued earnings guidance predicting its biggest profits in three years, with nearly double the operating profit of the same period a year ago. The company is set to report the confirmed results tomorrow.

Samsung’s press conference is ongoing; you can watch it here. The infographic below, provided by Samsung, has further information on the technical issues found with the Note 7 batteries.