It sounds like you're interested in installing Linux on a BlackBerry Q20 (Classic). I want to give you a realistic answer right away: it is not practically possible to install standard Linux (like Ubuntu, Debian, or even lightweight distros) on a BlackBerry Q20.
Mainline Efforts: Projects like postmarketOS have explored support, but it remains in a "non-working" or highly experimental state for this specific hardware. blackberry q20 linux install
While you cannot replace BlackBerry OS (BB10) with Linux, you can run Linux inside the existing system using specialized tools. It sounds like you're interested in installing Linux
Recommendation: For enthusiasts and those looking to experiment with Linux on mobile hardware, the BlackBerry Q20 is a viable option. However, it's essential to weigh the benefits against the potential risks, such as bricking the device. Ensure you follow installation guides carefully and understand the implications of unlocking your device's bootloader. Dual-booting (no bootloader chainload)
For the next four hours, the server room was silent except for the rhythmic clacking of Elias's keyboard. He was writing drivers on the fly, stitching together code from the Nokia N9 community and ancient Qualcomm documentation.