A couple years ago, I got a Nokia 2780 Flip. Here are the specs. They run for about $80-90 dollars these days.
I was tinkering with the phone in a way that I don't remember, and the bootloader was unlocked.
The screen that would show when I booted the phone after messing with it.
Flashing stock firmware
I wanted to flash the stock firmware to get things back to normal.
I stumbled upon this repository by dogination detailing how to get the phone back to stock.
Basically, on a Windows machine, you have to:
1) Download and extract the stock firmware from lolinet
2) Download and extract the Qualcomm QFIL flashing tool
3) Download, extract, and install the Qualcomm USB Driver
4) Download, extract, and install the Qualcomm QPST Tool
5) Copy "C:\Program Files (x86)\Qualcomm\QPST\bin\fh_loader.exe" to the same folder as the QFIL.exe tool
6) Put your Nokia in EDL (Emergency DownLoad) mode by powering the device off, and then powering it back on while holding Volume Up and Volume Down
7) Open QFIL.exe and select "Flat Build"
8) Click "Browse..." under "Select Programmer" and choose "prog_emmc_firehose_8917_ddr.mbn" from the extracted stock firmware
9) Click "Load XML..." under "Select Flat Build" and choose "rawprogram0.xml" and "patch0.xml"
10) Plug the Nokia in to your computer using a USB-A to USB-C cable, while the phone is in EDL mode (see step 6)
11) Click "Download" on the QFIL tool
12) Wait for the process to finish, this takes a while
13) Unplug the phone from the computer
14) Reboot the phone by holding the hang-up button until you feel a buzz
15) Boom! Stock firmware
Flashing custom firmware with root, adb, and more
TO-DO
Where I found instructions for stock firmware,