“Since the key is available to TrustZone, Qualcomm, and OEMs [Original Equipment Manufacturers] could simply create and sign a TrustZone image which extracts the KeyMaster keys and flash it to the target device,” Beniamini wrote. “This would allow law enforcement to easily brute force the FDE password off the device using the leaked keys.”

Source: How to Crack Android Full Disk Encryption on Qualcomm Devices