I installed the device firmware updater. I uploaded the files but it does not show the but the "update z wave firmware" button does not show up. I can't seem to find solution for this. I tried to reboot and changed web browser but did not work.
What model of hub do you have? It does not work on C-5 and older models, and your user account is old enough to suggest that you might have one of these.
They could probably add a note to this effect or restrict installation...originally, they didn't want to because they hoped to put Zigbee in the same app (probably also why it's generically named, not just Z-Wave). But they ended up doing that at the driver level instead...
On earlier hubs, you should still be able to use the special Z-Wave driver to update: [RELEASE] Z-Wave Firmware Updater
Oh I see. I have C-5. That's why T_T
Thank you @bertabcd1234 I tried this driver as well but somehow it always fail to update my inovelli red switch.
The Inovelli red switch can be a bit tricky to update. You need to pull the tab on the bottom of the switch at just the right time for it to work.
You mean the airgap, correct?
Mine got stuck at the upload phase. It did not pass beyong that. When did you pull the tab?
Yes, the air gap. 
I don’t recall exactly when it needs to be pulled - There’s a post in the thread that @bertabcd1234 linked above that explains when to pull it.
