Soft Brick
As the name goes "Soft" aka "Software" bricking is something that occurs when we perform a dirty flashing. Now you might think that what this dirty flashing means?
Dirty flashing occurs when you flash any ROM on your device without doing the factory reset. Or else if you flashed a ROM which was not made for your device!!
After fixing lots of devices of our favorite visitors, we got loads of good feedbacks. On basis of responses from all their devices while fixing, I acquired and gathered the solutions for the problems and divided the case of soft bricking into 2 stages.


Stage one: At stage one you will be able to boot into your recovery (custom/stock) one but you will be stuck at the boot animation (or on the brand's logo), in such cases you have to flash your stock ROM back on the device. Either by copying a factory signed zip file (if available) in your external SD card and flashing it via stock or custom recovery.


Stage two: If the situation is like you are not able to boot into your custom/stock recovery then you are at stage two. In these cases you have to use the Smart Phone flashing tools like:
• SP FLASH TOOL (for MTK chipsets)
• ODIN (for Samsung devices)
• Mi flash tool (for Xiaomis)
etc for flashing. So if the drivers are properly installed on the system which you are using then it will be able to detect your device in the "device manager" section on Windows.


Hard Brick
When the device has gone through problematic conditions such that it quits the detection of USB, charging and everything that you provide to it then the device is unfortunately hard bricked. Some hard bricked devices are as good as a paper weight that we paid for some day. But that is the extreme case lets see what are the two stages we can observe here:


Stage one: At stage one the device keeps getting disconnected every 5-8 seconds when you connect it with the flash tool via data cable (specially with the mtk devices I have seen). So in that cases we only have few seconds of time gap so that we can make the flash tool to detect the device. Hence, we have to find out certain key combos on the device which will lead to detection of your bricked device to flash the "stock ROM" while it kept connected to the data cable. Key combos could be:
* Volume Up + Power button
* Volume Down + Power button
* Volume Up + Volume Down
* Power button alone


Stage two: It occurs when some serious hardware damage happened to the device such as malfunctioning of the motherboard, Processors, Internal circuits etc. If the device reaches to this condition then it does needs repair on the segment of the hardware. In case if the device is under warranty then I recommend not to break the seal of the company or else the warranty will get void.


I think you got a little idea about the bricking of the devices and how to figure out if the device is hard or soft bricked.
Good luck and a happy yet cautious flashing to you all!