Can I flash a new bootloader using recovery (twrp)? fastboot/adb/computer cannot see the device

[kernelsandirs]

Can I flash a new bootloader using recovery (twrp)?

So if I plug my rooted Nexus 7(2013) in to any usb cable on any computer, it is just not detected(assuming usb port is dead at this point, only charges), Cannot even get adbd wifi to start and listen on port 5555 went through every possible scenario.( basically tried everything you can will throw at me, (MTP/PTP, usb debugging on/off, new cables, new computers, remove every possible android driver and re-install)
I saw one post where someone seemed to have a similar issue but was able to update the bootloader and his problem was solved!

Now I am not sure how he did it since I can't seem to find any good info on updating the bootloader directly from say TWRP I have no other access into the device remotely or via USB :-(

 

[Rukbat]

If it's not working when the phone is in normal mode (homescreen, phone works, etc.) it has nothing to do with the bootloader. I'd suspect the main Android ROM itself. You don't say what phone you have, but a full reflash may fix the problem. (Back up everything before you try anything.)