At least 2GB of free space for the core tool installation, plus additional storage for firmware files.
Kevin_GCE (likely a developer) announced on the forum that to resolve this hard-to-diagnose hang, promising a full release once tests were conclusive. gsm pack v2.6
Unlocking the Full Potential of GSM Pack v2.6: The Ultimate Guide for Mobile Technicians At least 2GB of free space for the