So I saw the new functions of the new version of the TI-84 Plus CE (that is, version 5.2), and I thought that this would be very nice for programming on my TI-84 Plus CE. So I decided to download and install the OS on my CE using TI-Connect CE.

I updated the calculator before; by dragging the downloaded OS onto my calculator on the Connect CE UI, it would pop-up this message saying that the RAM of the calc would be cleared if I installed the OS. So I archived my programs and proceeded to install the OS. Unfortunately, I didn't back up my programs, and I really wish I did before installing the new version (note to every self-respecting calc programmer out there).

After installing, the TI-84 Plus CE validated the OS and restarted the calc. However, it restarted with a completely white screen. It was like that for about a couple minutes, so I thought that a keypress was needed. So I pressed the on button, and nothing happened. I tried pressing any button, but nothing happened.

So I unhooked the calculator from my PC (my PC already noted that there was no connection beforehand). I tried pressing all the buttons again and turning the calculator off, but the white screen persisted to show. So I got a toothpick and pressed the reset button on the back of the calculator. This did turn off the calculator, but when turning it back on, it would show a white screen with several glitched textures. It would either do this, or slowly flash a white screen on the calculator. So I think my calculator is bricked.

So was it the update's fault, the transmission, or was I just being too impatient? The CE was on the latest version prior to the new version, and the TI-Connect CE software was also on the latest version. What did I do wrong, and is there any hope of bringing my calculator back to normal?

Any help would be appreciated.

I have no idea what went wrong. Possibly the connection was interrupted, or maybe the OS was incorrectly downloaded. I would try resending first the 2nd to last OS (the one you previously had on your calculator), then, if it works and you feel adventurous, try upgrading the OS again.

I'm not sure if that's really an option now. The TI-Connect CE no longer recognizes that my CE is plugged in even when it is "on" (aka showing the white flashing screens or glitchy textures). So I have no way of transferring the OS.
I'll call TI this weekend if no other viable solution pops up.

Luckily the boot code will save you. Press and hold the [2nd]+[del] buttons and then press the reset button in the back. Hope this helps

Success! Thank you so much Mateo for your help! I didn't even know there was a boot code as a failsafe to the calculator.
It was a bit weird pressing the buttons, but I found that pressing the three buttons quickly and simultaneously triggered the boot sequence.

Reinstalling version 5.1 didn't help, so instead, I cleared the memory via the boot code's clear command. Then I reinstalled the first version of the TI-84 Plus CE, and it worked.
Unfortunately, all the memory was cleared off my CE, but I guess it's my fault for not backing up my programs beforehand. Lesson learned.

Topic closed.

This is happening too frequently. I'm wondering how many support requests TI is getting regarding a corrupted OS. Maybe pin it somewhere in a CE subforum?