Does the Raspberry Pi need a BIOS?
Rasperry Pi uses Broadcom System on chip, info as follows,
All models feature a Broadcom system on a chip (SoC), which includes an ARM compatible central processing unit (CPU) and an on-chip graphics processing unit (GPU, a VideoCore IV). CPU speed ranges from 700 MHz to 1.2 GHz for the Pi 3 and on board memory range from 256 MB to 1 GB RAM. Secure Digital (SD) cards are used to store the operating system and program memory in either the SDHC or MicroSDHC sizes. Most boards have between one and four USB slots, HDMI and composite video output, and a 3.5 mm phono jack for audio. Lower level output is provided by a number of GPIO pins which support common protocols like I²C. The B-models have an 8P8C Ethernet port and the Pi 3 and Pi Zero W have on board Wi-Fi 802.11n and Bluetooth.
So now we see all this hardware, someone has to initialize them and make them functional before OS kicks in hence it need a firmware to do this for you. That what BIOS does, hence it must have BIOS or similar kind of firmware.
No, it doesn't.
Everything is done by the GPU, and after that, the kernel is loaded and CPU turns on. Here's the sequence: