Why do my identically prepared USB sticks differ in one byte?

I have two identical USB sticks (TrekStor 16GB) prepared as following with the c't bankix image.

1. 
   

   Preparation using GParted:

   
   
   
   
   • Deleted the existing partition
   
   
   • Created a new DOS partition table
   
   
   • Formatted the stick with FAT32, primary partition
   
   
   
   


2. 
   

   Loaded the image to the stick via usb-creator-kde.

   
   

So I did the identical procedure for both sticks, but one boots and the other crashes with an error message:

(initramfs) mount: mounting /dev/loop0 on //filesystem.squashfs failed: No such device
Can not mount /dev/loop0 (/cdrom/casper/filesystem.squashfs) on //filesystem.squashfs

Then I tried to compare them via sudo cmp /dev/sdb /dev/sdc. This resulted in:

/dev/sdb /dev/sdc differ: byte 441, line 5

What's wrong here, and how do I fix it?