Sonata system v0.3

This release contains the following on top of v0.2:

• Use Sonata JTAG ID code
• Documentation updates
• Implemented Elf bootloader
• Fixes to the Nix environment
• Enabling hardware revoker
• New testing framework

The main reason for this pre-release is to enable usage of the new RP2040 firmware (v0.4) and provide a release compatible with the latest sonata-software. This firmware uses UF2 for both FPGA bitstreams and Sonata firmware providing more reliable operation. Firmware is now written as an elf file into the flash and the sonata-software repository does not maintain support for the old method used by the v0.2 release.

It is recommended you use the v0.3 branch of sonata-software repository with this release. That branch will be maintained to remain compatible with this release.

Here's the flow for using these files:

1. Before plugging in your Sonata board, hold down the SW9 labelled "RP2040 Boot", and while holding this button plug your board into your laptop using the Main USB.
2. A drive called RPI-RP2 should pop up on your computer and copy rpi_rp2_v0.4.uf2 into it.
3. Make sure the bitstream select switch (immediately below the main USB-C port) is set to position 1.
4. This drive should automatically dismount once the file is transferred and remount as SONATA. Once the remount has happened, you can drag in the wrapped bitstream sonata-v0.3.bit.slot1.uf2. You may have to unplug and replug the USB cable if the drive does not mount automatically.
5. Once programming is successful, you should see the CHERI LED light up and the LEGACY LED turn off. If this is not the case, the bitstream loading may have failed and you should retry by unplugging and replugging the main USB on the Sonata board and re-drag the bitstream into the SONATA drive.
6. After programming the bitstream, drag the sonata_simple_demo_v0.3.uf2 into the SONATA drive.
7. You should now see the user LEDs turn on and off, as well as the lowRISC logo appear on the LCD.