Yes, the G75 BIOS are prone to fail when swapping drives. Can't do anything about that.
1. Use Macrium Reflect software (Free Version) to copy your drives.
2. Remove your secondary drive throughout procedures.
3. Use a USB to SATA cable to attach your new drives while copying your drives. Don't use the built-in secondary SATA connector. Possible link to BIOS failure.
4. First, copy your 256GBSSD to your new 1TBSSD attached to the USB to SATA connector. Then replace the 256GBSSD with the new 1TBSSD.
5. Reboot your laptop (secondary drive still not in place) several times, make sure everything looks good.
6. Now install your old secondary 1TBHD and reboot the laptop and insure things still are good.
7. Using Macrium Reflect software, copy your secondary 1TBHD to your new secondary 1TBSSD attached to the USB to SATA connector.
8. Swap your secondary drives, reboot, make sure everything is great.
Here's a link for USB to SATA cable:
https://www.newegg.com/p/181-00D8-00004?cm_sp=SearchSuccess-_-INFOCARD-_-usb+to+sata+cable-_-9SIAME8...Now for a different solution:
Here's a link for a Hard Drive Duplicator/SSD Cloner:
https://www.newegg.com/wavlink-wl-st334u-red-us-dock/p/0VN-0069-00014With this device you can clone your drives without need of any other software. I have one of these and have used it many times. Offline clone capable.
1. Remove both old drives from laptop.
2. Plug-n the Duplicator to power.
3. Insert old 256GBSSD and new replacement 1TBSSD and clone. Remove drives.
4. Insert old 1TBHD and new replacement 1TBSSD and clone. Removes drives.
5. Install the new drives in the laptop. Reboot. Make sure everything is working correctly.
Good Luck
G752VSK, G75VW-3D, G51J, G1S
Homebuilt Windows Server