You don't use firmware links from that thread. You'll need to download firmware for your device. Those files are "model locked" (= you can't use/install PW2 files on PW1). The only thing you need is info contained in that single post (that was the reason I linked to single post and not entire thread or its firs post).
The info is what should your do:
1) connect Kindle to your PC
2) copy correct bin file for YOUR Kindle
3) DON"T disconnect your Kindle
4) force Kindle restart by holding the power button for X second (amount of time needed to trigger a restart instead of "sleep mode"
You need to find and download firmware update to 5.4.4.2. You should probably first try to search MobileRead for thread containing list of firmware update files grouped by models.
This link is from Amazon's servers and should be the one you need:
https://s3.amazonaws.com/G7G_Firmwar...le_5.4.4.2.bin
BUT double check that if you can... because I no longer have previously downloaded bin file (I have but no longer use my old PW1, which also was never updated to that firmware, its on firmware 5.4.4 (without .2) so can't compare MD5 checksum to be 200% certain that link above is the correct one.