Thank you for contacting Intel Communities.
The PCH on the chipset installed on your laptop supports data volumes up to 256 TB, therefore; there isn't any restriction from the chipset side to upgrade to a 2 TB HDD.
On the other hand, I would check with the manufacturer (Asus) for any restriction from their side.
Please check this article for more information.
Hope this information helps.
Many thanks for your helping.
I just receive some answer from ASUS's staff as follows:-
1. They block the maximum of HD capacity (up to 1TB).
2. Reason: Prevention from Heat, Notebook design limit (WD and Seagate have 2TB HD in 7mm size today), Chipset durability.
If you can do some favor for me, Please tell me how to recheck it? Such as BISO check or only try to install 2TB HD. for compatibility or try to connect any size of > 1TB HD via USB3 port.
UX 303 LB
Intel® Core™ i7-5500U 1.8GHz
Intel® Core™ i5-5200U 1.6GHz
NV 940M + Intel® HD Graphics 4400
DDR3L 1600MHz 4GB (on board) + 2G / 4G/ 8G Slot Dim
13.3” 16:9 178 FHD (1920 x 1080)
Pure 7mm HDD up to 1T
Hybrid HDD: 500G HDD +8G SSD
SSD: up to 256G
802.11 a /g/n & 802.11 ac
External cable support 10/100 Mbps Ethernet
Built-in Bluetooth v2.1 + EDR
BT 4.0 support (on WLAN+ BT 4.0 combo card)
HD 720p CMOS module
Windows® 8.1 Home Basic 64 bit
Windows® 8.1 Home Premium 64 bit
Windows® 8.1 Professional 64 bit
1 x mini Display port
3 x USB 3.0 port
1 x HDMI 1.4 (1080p support)
1 x audio jack combo
1 x SD card reader
Built-in B & O ICE power® audio system
Output 19V 65W
Input: 100~240V AC, 50/60Hz universal
Dimension & Weight
323mm x 223mm x 20mm 1.45 Kg
Asus confirmed what I mentioned earlier; even though the chipset may support certain features/options, the OEM may restrict them.
You shouldn't have any issues connecting an external HDD via the USB3 port, however; you may run into some incompatibility with some drives (you will need to confirm compatibility with Asus).