Can't add Persistence to Kali LIve USB

Hi, I have a 128GB USB 3.0 I'm trying to add Kali 64-bit Live USB with Persistence. I've done it before. I'm on Windows 10. It boots Kali fine. When I add the commands (see below) and reboot it doesn't save the test Leafpad "Test" on the Desktop. Formatted FAT32. Here's my steps... Used MiniTool Partition to format FAT32, Rufus with Kali 2019.2 ISO, MiniTool split 3.5GB "KALI LINUX", 111GB "Persistence" and applied (10-15 minutes.) Everything looks good. I can boot into Kali and choose "Live USB with Persistence." Then I open terminal and enter commands:

fdisk -l
(fdisk shows sdb1 and sdb2 KALI LINUX and Persistence)
mkdir -p /mnt/kali
mount /dev/sdb2 /mnt/kali/
echo ?/ union? > /mnt/kali/persistence.conf
umount /dev/sdb2
reboot

When I reboot and it loads Kali Desktop, I don't see my "Test" leafpad and it doesn't save anything. No Persistence. I tried Universal USB Installer and it created with 1 partition "E:Run Debian GNU/Linux." Not 2 partitions with one called Persistence. I can boot into Kali and it seems faster than the 2 Partition Rufus. I run the above commands and add a Leafpad to the Desktop and reboot. Goes into Kali and there's no Leafpad so I'm guessing it did not add Persistence. I've had Kali with Persistence working on this 128GB before but had to remove it (months ago.) I think I used Rufus. I know I used MiniTool and split. So is there any other commands besides the above? Does anyone kno why it's not working? ABOVE is echo "/ union" > /mnt/kali/persistence.conf. Copied and paste didn't work right on this thread. Please reply. Thanks

Hello, I got it working. The problem was I spelled Persistence with a capital P on MiniTool and then lower case in terminal. The below worked. Super Happy.
mkdir -p /mnt/usb
mount /dev/sdb2 /mnt/usb/
echo "/ union" > /mnt/usb/persistence.conf
umount /dev/sdb2
reboot