Flash Galay S 3 Mini on Linux

I tried to root my Samsung Galaxy S3 Mini (GT-I8190) to pull the boot.img to flash a custom kernel.

However rooting doesn't seem to be that easy for the Galaxy S3 mini. I was recommended to flash a custom recovery (CWM) to be able to install a random ZIP update file, which is rooted. (I can't believe, it's that difficult, but it seems like...)

So I downloaded all the necessary files (CWM and Update.zip) and looked for a Flashing software. Quickly saw, that fastboot didn't work (Seriously Samsung?!). So I looked for other tutorials NOT including Odin, since I'm working on Arch Linux. I finally found Heimdall and built it.

So I thought I could now flash the recovery. In my PIT, the Partition no. 20 (Index 19) and with the name "Kernel2".

So I tried to flash it: heimdall --Kernel2 recovery.img and heimdall --19 recovery.img. Both reported success, on both methods, the device download screen showed, that the download was complete and the device rebooted.

Still stock recovery

I even tried to flash the Android kernel (Index: 20, Name: "Kernel") with my compiled boot.img, which didn't contain a ramdisk (I don't care, if the device is lost. It's a test device). And it booted. With stock Android.

What's even wierder, is that my device shows:

CUSTOM BINARY DOWNLOAD: YES (5 counts)

CURRENT BINARY: CUSTOM

SYSTEM STATUS: CUSTOM

So it did in fact receive the images, but didn't flash them somehow.

Thanks for reading that question and even more thanks for helping!