FX-7400GII OS Upgrade Issue

Hello.
So i was following the OS Upgrading process of a tutorial shared with me via and old post i made and this is what happened:
I checked my calculator requirements, downloaded some upgrade .bin files, processed them with PolyOS software and tried to flash the one i selected to the calculator using FX-Remote 2.03, it got the file, the calc recieved some data and a pop appeared saying that it detected a GII model and i had to wait for it to display "waiting" and then continue but the device gets stuck at the unknown BIOS (serial numbers i guess) and press restart button but it doesn't display what it should causing the failure of the process so i have to go through it all over again with no result so, can somebody help me solving this problem please, if possible please reply.
Thanks in advance.
PS: the upgrading tutorial link is the following:
https://tiplanet.org...hp?f=96&t=19592