Install Sidecar (Raspberry Pi 4B)

Sidecar, the full version on the Raspberry Pi 4B, runs bare metal: there is no Linux and no login. It boots straight into the engine from its SD card. It works together with the Rytm mods, so patch and flash those first (Patch and flash the Rytm).

You need

A Raspberry Pi 4 Model B (2 GB or more), its 5.1 V 3 A USB-C supply, and a microSD card (its contents are replaced).
A USB A-to-B cable to the Rytm.
Optional: an 800x480 HDMI display (USB touch works too) and an Ethernet cable.
From the Releases page: sidecar-pi4-sd-<commit>.zip and its .sha256, and the plugins/ folder (optional, the starter user machines).

Make the SD card

Check the download: shasum -a 256 sidecar-pi4-sd-*.zip must match the .sha256 file.
Format the card as FAT32 with one partition (MBR):
- macOS: Disk Utility > Erase, Format “MS-DOS (FAT)”, Scheme “Master Boot Record”.
- Windows: the SD Association’s “SD Card Formatter”, or format X: /FS:FAT32 for cards of 32 GB or less.
- Linux: mkfs.vfat -F 32.
- Raspberry Pi Imager’s “Erase” does it too.
Unzip the file and copy the files themselves (not the folder) to the card’s top level.
Eject the card and put it in the Pi.

File	What
`start4.elf`, `fixup4.dat`, `bcm2711-rpi-4-b.dtb`	the Raspberry Pi boot firmware (unmodified; see `LICENCE.broadcom` and `COPYING.linux`)
`armstub8-rpi4.bin`	the ARM boot stub (from Circle)
`config.txt`	boot settings: the display, then the Sidecar boot block
`cmdline.txt`	Sidecar options, one line
`sdboot.img`	the small loader that checks and starts the engine
`engine.img`	the Sidecar engine

Connect and power on

 Analog Rytm MKII [USB-B] ---- USB A-to-B ----> [USB-A] Raspberry Pi 4B [USB-C] <---- power supply
                                                        [micro-HDMI 0] --> 800x480 display (optional)
                                                        [Ethernet] ------> computer (optional)

Use a USB-A port for the Rytm, with no hub.
On the Rytm: SETTINGS > SYSTEM > USB CONFIG set to the Overbridge mode. That is the only setting the Sidecar needs: the Rytm’s MIDI port settings (USB MIDI in and out) do not have to be changed for the voices, send effects, user machines or remote pages (tested on hardware). Only STUTTER’s tempo sync and the recorder’s armed mode use the Rytm’s clock and transport over USB (MIDI CONFIG: CLOCK SEND and TRANSPORT SEND).
Connect the display before power-on: the screen is set up at boot.
Power on. A boot screen with a progress bar appears within a second of the engine starting; the engine runs about 11 seconds after power-on.

First boot over Ethernet: sidecar.local

The Pi serves a web page with the status, the live log and its controls.

Connect an Ethernet cable directly from the Pi to your computer.
Open http://sidecar.local.

How it finds each other:

The Pi has a fixed link-local address, 169.254.61.60. A computer with no address set on that port gives itself a 169.254.x.y address after a few seconds (macOS and Windows do this by default), so the page works with no network settings at all.
If your computer’s port has a manual address, set it to 169.254.61.59, netmask 255.255.0.0. Or set ip= and netmask= in cmdline.txt to fit your network.
There is no DHCP client on Ethernet, so a router network only works with a matching ip=.
sidecar.local is answered by the Pi itself (mDNS). A second Sidecar on the same network becomes sidecar-1.local.
The page has no password. Use it on a direct cable or a network you trust.

Wi-Fi is off in the package; see Wi-Fi (off by default) below and Wi-Fi.

Options (`cmdline.txt`)

One line of name=value options, separated by spaces. The release sets sdport=0, which turns off writing boot files over the network. Leave it in.

Option	Default
`out=tracks\|main`	tracks	voices on their tracks’ channels (what the mods expect), or summed on MAIN (a stock Rytm)
`notes=on\|off`	off	the Rytm’s MIDI notes trigger voices (not needed with the mods)
`display=0\|1`	1	the HDMI display and touch
`web=0\|1`	1	the web page at `http://sidecar.local`
`ip=`, `netmask=`	169.254.61.60, 255.255.0.0	the Pi’s Ethernet address
`width=`, `height=`	the display’s	the frame buffer size, for a display other than 800x480
`touchscreen=minx,maxx,miny,maxy`		touch calibration, if the touch is off
`screensaver=MIN`, `brightness=PCT`	60, 100	override the display settings at boot
`recbuf=MB`	64	the recorder’s memory; 0 turns recording off

Example: sdport=0 display=0 for a Pi without a display.

The display

config.txt sets HDMI to 800x480 at 60 Hz:

[all]
hdmi_force_hotplug=1
hdmi_group=2
hdmi_mode=87
hdmi_cvt=800 480 60 6 0 0 0
disable_overscan=1

For another display, change the hdmi_cvt line to its resolution and add width= and height= with the same values to cmdline.txt. Leave the block that starts # sidecar sdboot begin as it is: without it the Pi does not start the engine.

Starter content

The SD card package already holds the starter content: /JUNO/Factory/ (the Juno-106’s 128 factory patches) and /DX7/ (three 32-voice DX7 banks), with STARTER-CONTENT-README.txt and its notice. It is also a zip of its own, sidecar-content-<version>.zip, on the Releases page: extract it to the card’s root (or upload the folders on sidecar.local, Files, Upload folder) if you set up the card before. It only adds files; your own files stay.

On the Rytm: the sample browser’s SIDECAR folder → JUNO/Factory or DX7 → LOAD TO PROJ adds a patch to the project’s list, and the JUNO or 6-OP FM machine’s PAT knob steps through it.

Starter user machines

The release’s plugins/ folder holds six starter machines as Pi packages: sc_acid.a64.rmp, sc_wavepad.a64.rmp, sc_metal.a64.rmp, sc_snare.a64.rmp, sc_pluck.a64.rmp, sc_grain.a64.rmp (MIT; check them against SHA256SUMS). Upload them on sidecar.local, tab Machines, or copy them into /Plugins/ on the card before you put it in the Pi. The Teensy’s .rmp files do not load on the Pi.

The remote UI

The remote pages of the rui1027d Rytm build (TRK + YES on the Rytm) need this release’s kernel (1021 or later); tested on hardware. With an older kernel the pages open without any text. The first version is based on Analog Rytm MKII OS 1.73. OS 1.74 will be supported after testing.

Wi-Fi without a cable: sidecar-wifi.txt

in testing To set up Wi-Fi with no Ethernet cable and no web page, put a text file called sidecar-wifi.txt at the root of the Pi’s SD card (the top folder, next to Plugins; it shows in the Mac Finder and Windows Explorer). Three lines are enough:

ssid=MyNetwork
psk=MyPassword

Make sure the Wi-Fi chip firmware is on the card in /firmware/ (see below).
Save sidecar-wifi.txt at the card root, put the card in the Pi and power it on. The Pi reads the file at the next boot, before Wi-Fi starts.
The Pi joins the network (DHCP, sidecar.local). It stores only the derived key, never your password, in /.rytm/wifi.txt, and then deletes sidecar-wifi.txt from the card (if it cannot delete it, it overwrites the contents and renames it sidecar-wifi.used).
If the network does not come up within 90 seconds (wrong password, not found, no address), the Pi falls back to its previous setting (Ethernet when Wi-Fi was off) and restarts, so a typo cannot lock you out.

Options (one per line): band=2g, band=5g or band=any (2.4 GHz is the default), and open=1 for an open network without a password (leave psk= out). password= works as another name for psk=. Lines starting with # are comments; spaces around = and quotes around the values are fine. The password is 8 to 63 characters, or a 64-digit hex key; the network name is 1 to 32 characters.

If the file cannot be used, the Pi deletes it anyway and writes sidecar-wifi-error.txt at the card root with a short reason (for example “password must be 8-63 characters”); it never contains your network name or password. Fix the file and try again; a successful import removes the error file.

The alternative is the web page’s Wi-Fi settings (Status tab, over Ethernet). Never share the card, or a photo of it, while sidecar-wifi.txt is on it: the password is in it in plain text until the next boot.

Wi-Fi (off by default)

The SD card package has Wi-Fi off: it ships no Wi-Fi settings and no Wi-Fi chip firmware. Joining works on hardware; the Wi-Fi settings section on the web page’s Status tab (scan, Connect and save, a 90 s fallback) is in testing. The network is either Ethernet or Wi-Fi, chosen at boot. To try it:

Put the Pi 4’s Wi-Fi chip firmware in a folder /firmware/ on the card: brcmfmac43455-sdio.bin, brcmfmac43455-sdio.clm_blob and brcmfmac43455-sdio.txt. They come from the Raspberry Pi firmware-nonfree repository (cypress/cyfmac43455-sdio-minimal.bin and cypress/cyfmac43455-sdio.clm_blob, renamed, and brcm/brcmfmac43455-sdio.txt), under their own licences.
Boot with Ethernet, open sidecar.local and, in the command line, enter wifi=scan to list the networks, then wifi=join:<network>:<passphrase>. The Pi stores a derived key in /.rytm/wifi.txt, never the passphrase itself, and never logs it. Reboot: the Pi joins with DHCP and stays sidecar.local.
wifi=off goes back to Ethernet at the next boot. To forget the network, delete /.rytm/wifi.txt from the card.

You can also write /.rytm/wifi.txt by hand:

on=1
country=GB
band=2g
ssid=YOUR-NETWORK
psk=YOUR-PASSPHRASE

country= is your two-letter country code; band= is 2g (the default; 5 GHz DFS channels did not get an address in our test), 5g or any. A file written by hand holds the passphrase in plain text, so prefer wifi=join. Never share a card, a log or a screenshot that contains this file. The web page has no password: on a shared network anyone can open it.

First setup without a cable (in testing): a sidecar-wifi.txt file at the card’s root with ssid= and psk= lines is imported at boot (only the key is stored, the file is deleted; a problem goes to sidecar-wifi-error.txt). The Wi-Fi chip firmware in /firmware/ is needed as above.

Updating and going back

To update, copy the new release’s files over the old ones on the card. Your samples, recordings, /Plugins/ and /.rytm/ stay. Each package’s BUILD-INFO-pi.txt names the kernel it carries.
To stop using Sidecar, reformat the card. Nothing on the Pi itself is changed.

Check that it works

Power the Pi with the Rytm connected (with the patched OS).
On the Rytm, pick an EXT machine on a track and play it. Then set a SEND FX TYPE, such as CLOUDSEED, and send a track to it with AMPLITUDE 2.
The display, or sidecar.local, shows “Rytm connected” and the engine’s status.

If something is off, see Troubleshooting, then open a tester report.