There are 3 different hardware revisions of GS748T -

GS748T V1H1 (Hardware revision #1), GS748T V1H2 (Hardware revision #2) & GS748T V1H3 (Hardware revision #3)

You can identify the revision of your GS748T from the product serial number:

GS748 V1H1 Serial number starts with "GS27" or "141", e.g., GS27xxxxxxxxx or 141xxxxxxxxx
GS748 V1H2 Serial number starts with "1DT" or "1LC", e.g., 1DTxxxxxxxxx
GS748 V1H3 Serial number starts with "1MC" or "1PK", e.g., 1MCxxxxxxxxx

The GS748T V1H2 and V1H3 can also be identified by the label on the rear panel of the switch, which includes "V1H2" in the HW field, as highlighted below.

GS748T V1H2 Label Detail

Important alert before choosing the firmware:

Do NOT upgrade GS748 V1H1 to firmware version 2.0.1_01. After you upgrade, you will not be able to downgrade back to the previous version. Instead, upgrade GS748 V1H1 to firmware version 2.0.2_02
You cannot downgrade GS748T V1H2 or V1H3 to any 1.x firmware. GS748T V1H2 ships with 2.0.1_01 by default. GS748T V1H3 ships with 2.0.2_02 by default.

Hardware Version	Latest Firmware Version
GS748T V1H1	Version 2.0.2_02 Version 1.3.0 Version 1.1.0
GS748T V1H2	Version 2.0.2_02 Version 2.0.1_01
GS748T V1H3	Version 2.0.2_02

This product includes software code developed by third parties, including software code subject to the GNU General Public License ("GPL") or GNU Lesser General Public License ("LGPL"). As applicable, the terms of the GPL and LGPL, and information on obtaining access to the GPL Code and LGPL Code used in this product, are available to you at NETGEAR's Open Source Code Web page. The GPL Code and LGPL Code used in this product is distributed WITHOUT ANY WARRANTY and is subject to the copyrights of one or more authors. For details, see the GPL Code and LGPL Code for this product and the terms of the GPL and LGPL.

GS748Tv1 Firmware Selection Instructions