You might want to reinstall the stock firmware. That should make your device bring back to life. To do that, please download one of the available firmware images from sammobile.
Please note: I'm assuming your model number is "SM-T530NU". Check that again. If this is not your device model number, please don't try these steps without the correct files for your device. Use the latest available firmware and download it. To flash it, simply follow the instructions on the download site.
- Extract (unzip) the firmware file
- Download Odin v3.10.7
- Extract Odin ZIP file
- Open Odin v3.10.7
- Reboot Phone in Download Mode (press and hold Home + Power + Volume Down buttons)
- Connect phone and wait until you get a blue sign in Odin
- Add the firmware file to AP / PDA
- Make sure re-partition is NOT ticked
- Click the start button, sit back and wait few minutes
Afterwards, you may want to try to root your tablet again. Please refer to this thread: How to root a 10.1 Tab 4 (T530/NU, T531, T535), also links for 8.0, 7.0. Thanks to user thisisapoorusernamechoice on XDA for providing such a detailed answer.
Preparation: Read everything and make sure you understand. I attached Odin v3.09 and v3.10.6. I've always used 3.09 successfully but other users have had problems with it and used 3.10.6 successfully instead. Download the one you want and extract the zip to PC desktop. Also on the tablet enable usb debugging and mock locations in developer settings. Make sure you have the proper USB drivers for your PC. A quick note on file names: development code names for the Tab 4 series are as follows: matisse = 10.1, millet = 8.0, degas = 7.0
- Download the openrecovery-twrp-220.127.116.11-matisse_wifi_3g_lte.tar file and save to PC. Download the superSU zip file and save to tablet storage. Obviously save the files somewhere easy to remember, and easy to navigate to.
- Power off tablet. Boot into download mode (hold vol-, home, and power all at once in that order), then hit vol+ to continue
- Run Odin. Disable the "Auto-Reboot" and "Re-Partition" options, this is critical to success
- Connect tablet via USB. Hit AP button in Odin, select the TWRP tar file
- Flash (click start). When it's done, the progress bar will be full and Odin should say something like "RESET!"
- Hold the power button to power down the tablet. Then immediately hold vol+, home, and power (all at once, in that order) to boot into recovery.
[This must be done before rebooting normally!]
- Install the SuperSU zip file that is saved to your tablet (tap the install option in TWRP, navigate to the zip file)
- Reboot system (normal reboot). When android is booted, run the superSU app and follow the prompts; i.e. update the binary if it asks you to, choose normal install, be patient while it installs (takes a while) and reboot if it tells you to
If you have followed the steps correctly, your device should run a rooted Lollipop ROM.