I have been doing some tests on my router (TL-WR841N) by flashing DD-WRT and OpenWRT firmwares instead of the stock TP-Link firmware (by doing that directly from the stock firmware web interface). And then I reverted the firmware from both OpenWRT and DD-WRT back to the stock firmware (using Tftpd method without any external serial connection) and everything went fine.
But a couple of days ago, I found in OpenWRT official documentation, that when I want to revert back to Stock firmware from OpenWRT or DD-WRT, I have to remove the beginning sector of the stock firmware image (if its name has boot word).
Actually my stock firmware has boot word, but nevertheless, I flashed the stock firmware WITHOUT removing anything from image and it worked perfectly!
I couldn't understand why should I remove that part of the image?
If it is important as they say, why it does work with me although I didn't removed it?
What bad things can happen if I continued reverting from OpenWRT back to stock firmware ignoring removing that beginning part of the stock firmware?