It sounds magical. It is also physically impossible. But the fact that people keep searching for it tells a bigger story about frustration, e-waste, and the difference between protocols and physics . To understand why this software cannot work, we have to look inside your USB modem.
A 3G modem (UMTS/HSPA) contains a specific and a radio frequency (RF) front-end tuned to operate between 850 MHz and 2100 MHz using W-CDMA modulation. 3g modem to 4g converter software
On these very specific devices, flashing official “stick-to-modem” conversion tools updates the firmware to enable the dormant 4G radio. It sounds magical