Building an Overlook Cache with a Raspberry Pi 5, with or without an NVMe SSD

Updated October 17, 2026 · by the Overlook team at CTT Apps (about us)

An Overlook Cache is a Raspberry Pi that plugs into your Rivian where the USB drive used to go. The car records Gear Guard, incidents and saved clips to it like any drive, and whenever the Cache is on Wi-Fi it backs new recordings up to your Overlook cloud by itself, before the car can record over them. This guide covers the two Pi 5 builds we recommend: one with an NVMe SSD (the one we use) and a cheaper one that keeps everything on a microSD card.

Pick a build

Why the SSD is worth it: on a card-only Cache, everything the car records goes through the card, four cameras at a time, while the Cache reads the same card to back recordings up. Cards handle that, but they wear, and many slow down sharply at the small random writes a car makes. An NVMe drive shrugs both off, reports its own health (life used, media errors, temperature, data written), and lets the Cache mount its SD card read-only. You can start with the card build and add the SSD later without starting over: the Cache moves the car’s drive to the SSD from the app.

Parts: Pi 5 + SSD

Alternative to the Argon case: the official Raspberry Pi M.2 HAT+ (it takes 2230 and 2242 drives) or any other M.2 HAT for the Pi 5 that connects through the PCIe ribbon, in a case with room for it and the Pi 5 Active Cooler or a fan.

Parts: Pi 5, card only

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You’ll also need a computer with a microSD card reader (to write the card), any USB-C phone charger for setting it up at home, a small Phillips screwdriver, and Overlook Plus for the cloud backups. The Cache software is free.

Step 1: write the card

1. Install Raspberry Pi Imager (free, from the makers of the Pi) on your computer.
2. On the Overlook Cache page, choose Pi 5, then Open in Raspberry Pi Imager. Imager asks to switch to a custom repository: choose Switch.
3. Choose your board, Overlook Cache, your card, then Write. Imager checks the card and ejects it when it’s done (a few minutes).

SSD build: use the SSD from the first start (optional)

Before you take the card out, open the small boot partition Imager made, copy overlook-box.example.txt to overlook-box.txt and add the line store=ssd. The Cache then puts the car’s drive on the SSD the first time it starts. It erases the SSD to do it; if the SSD already has partitions on it, it leaves it alone unless you also add store_erase=yes. Skip this and you can switch from the app in step 4 instead.

Step 2: put it together

SSD build (Argon NEO 5 NVMe case)

1. Fit the SSD into the M.2 slot on the case’s bottom board and fix it with the screw that came with the case. Use the thermal pad if your case includes one.
2. Connect the short PCIe ribbon cable from that board to the Pi 5’s small connector marked PCIe, with the contacts facing the way the case’s instructions show, and close both latches fully. A loose or reversed ribbon is the most common reason an SSD doesn’t show up.
3. Plug the case fan into the Pi 5’s fan connector, put the Pi into the case and close it.
4. Put the microSD card in the Pi’s card slot.

With the official M.2 HAT+ instead: screw the standoffs to the Pi, connect the ribbon to the Pi’s PCIe connector and the HAT the same way, seat the HAT on the standoffs, then fit the SSD into its slot.

Card build

1. Put the Pi 5 in its case and plug the fan into the fan connector.
2. Put the microSD card in the Pi’s card slot.

Step 3: start it and set it up

1. Power it at home from any USB-C charger. The first start takes a few minutes while it prepares the car’s drive.
2. Within 30 minutes, open the Overlook app (or your account on watch.overlookcam.app in Chrome or Edge) and go to Account → Overlook Cache → Set up a Cache nearby. It connects over Bluetooth: pick the Cache, choose your home Wi-Fi, and it links to your account. Missed the window? Unplug it and plug it back in.
3. Add your Rivian’s Wi-Fi hotspot too (Cache → Wi-Fi → Add a network) if you use it, so the Cache can back up while you drive, and mark your home Wi-Fi as preferred. More on the car’s hotspot.

Step 4 (SSD build): move the car’s drive to the SSD

If you didn’t add store=ssd in step 1, open Cache → Storage & reliability in the app and choose Use next to your SSD (it’s also on the Cache’s own status page). It asks before erasing the SSD, again if the SSD has partitions on it, and again if anything on the current drive isn’t backed up. The car then gets a new, empty drive on the SSD. The old drive is kept on the SD card (/var/lib/overlook-box/store.xfs) until you delete it to free the space.

Copying the old drive across isn’t offered on purpose: moving 100 GB or more off an SD card takes half an hour or longer, and the car would have no drive to record to all that time. Back up what you need, then switch.

What the Cache does with the SSD

It erases the SSD and makes one partition with the XFS filesystem, labelled overlook-ssd, mounted by that label. On it goes the car’s drive: a disk image, FAT32 by default, named OVERLOOK, sized at about three quarters of the space (at least 128 GB, never more than 2 TB, the range Rivian supports). The 500 GB SSD above gives a drive of about 375 GB. The rest holds snapshots: when the Cache backs a recording up, it makes an instant copy-on-write snapshot of the drive and reads that, never the image the car is writing to.

Once the drive is on the SSD, the Cache never falls back to the SD card. If the SSD goes missing, it reports “SSD not found or failed” and the car has no drive until it’s back. That’s deliberate: silently recording to a different, smaller drive would hide a problem until you went looking for footage. With the drive on the SSD you can also turn on the read-only system in the same screen, so the car cutting the power can never damage the card.

Step 5: plug it into your Rivian

1. Unplug the USB drive the car records to, and plug the Cache into the same USB-C port in the center console with the data cable. (The rear ports only charge.)
2. If the car offers to format the drive or run its speed test, let it.
3. If the car asks which USB drive to use and lists two, pick the one whose name matches the Cache: the app shows it on the Cache screen, for example USB Drive (EBD1-BD08). A second entry is a different drive still connected. Why the car shows two drives.
4. Turn Gear Guard video on, then in the app run Cache → In-car check. It confirms the car sees the drive and checks the USB link, power, storage speed, drive size and port.

Step 6: check backups

The next time the Cache is on a known Wi-Fi network, new Gear Guard events, incidents and saved clips appear in the Cloud tab of the app, usually within minutes. The Cache screen shows a storage bar (backed up, waiting, free), what it’s backing up now, and anything that needs attention. You’ll get a notification for new Gear Guard events once they’re backed up.

For a closer look on the SSD build, list the disks over SSH:

lsblk -o NAME,SIZE,MODEL,TRAN,LABEL

The NVMe drive shows up as nvme0n1, and once the Cache has set it up, its partition carries the label overlook-ssd.

Power and the car sleeping

The Pi 5 is powered through the same USB-C port that carries the car’s data. Raspberry Pi’s own supply gives 5 V at 5 A; a car port gives less, and a Pi 5 that hasn’t been told its supply can do 5 A limits its USB-A ports to 600 mA in total. That limit is about the USB-A ports, one more reason to use NVMe on the PCIe connector rather than a USB SSD. A Pi 5 with an NVMe SSD draws only a few watts.

The Pi 5 measures its own input voltage and power draw, and the Cache checks for under-voltage every 30 seconds. If the app shows the power dipping, try a shorter, better cable or another port first.

The Cache goes off when the car turns its ports off to sleep. That can cut a backup short; the Cache picks it up again next time. To give it time to finish after you park, turn on the car’s outlets timer (Energy → Outlets). How long to set it.

More about the Cache, and the card image for every board: Overlook Cache.

Related guides

• Choosing an SD card or SSD for Rivian Gear GuardWhat A2, V30, U3 and “high endurance” promise, why random writes matter, and how to test what you bought.
• Keeping recordings when your Rivian sleeps: USB power and the Outlets timerWhy the USB ports go dead after you park, what that does to a backup, and how long to set the Outlets timer.
• Why your Rivian shows two USB drives, and how to tell them apartWhat “USB Drive (EBD1-BD08)” means, where that code comes from, and how to read it on any computer.