Scout Lite onboard microSD ESP32-C5 wardriver for Flipper Zero

What microSD Card for ESP32 Marauder Wardriving? Size, Format & Fixes (2026)

PINGEQUA Lab · ESP32 Marauder wardriving · 7 min read · Updated 2026-08-03

ESP32 Marauder's wardrive mode logs every access point it sees — SSID, BSSID, GPS fix — straight to a CSV file on the microSD card. Get the card wrong and Marauder won't detect it, won't mount it, or quietly writes a broken log. Here's the exact size and format it wants, plus fixes for "SD card not detected."

Quick answer Marauder needs a microSD card 32 GB or smaller, formatted FAT32. Anything bigger (64 GB+) ships exFAT by default and isn't reliably supported — mounts fail or logs come out corrupted. Format steps and detection fixes are below. Scout Lite ships with an onboard microSD already set up.

The rule: 32 GB or smaller, FAT32

Marauder's own FAQ is explicit: the SD card has to be 32 GB or smaller and formatted FAT32. Both conditions apply together — a 64 GB card force-formatted to FAT32 still fails the size half of the rule, and a 32 GB card left on exFAT still fails the format half. Source: Marauder wiki, "SD Card Not Found" FAQ entry.

This isn't a Marauder quirk — it's how the ESP32 SD/MMC libraries that most sketches (Marauder included) build against handle filesystems. FAT32 support is baked in; exFAT support usually isn't, unless a project deliberately adds a separate exFAT driver. Marauder doesn't. So the safe buy is a plain 8 GB, 16 GB, or 32 GB microSD — wardrive CSV logs are text, they don't need capacity beyond that.

Why bigger or exFAT cards fail

The SD Association's own spec splits cards into three classes by default filesystem: cards up to 2 GB are SD (FAT12/16), 4 GB–32 GB are SDHC (FAT32), and 64 GB up to 2 TB are SDXC — which the spec defaults to exFAT, not FAT32. That means any 64 GB, 128 GB, or 256 GB microSD you buy off the shelf arrives exFAT-formatted out of the box. You didn't choose exFAT; the card class chose it for you.

Drop one of those into a Marauder device and the failure modes vary: sometimes it's an outright "SD card not detected" or mount error, sometimes the card mounts but wardrive logs come out empty or truncated, sometimes it works for a session and then drops out. None of that is a hardware defect in the card — it's a filesystem the firmware's SD stack isn't built to parse.

How to format to FAT32

For a card 32 GB or smaller, both major OSes handle this natively:

  • Windows: right-click the SD drive in File Explorer → Format → set File System to FAT32 → Start. Windows' built-in Format dialog only offers FAT32 for volumes up to 32 GB.
  • macOS: open Disk Utility → select the card → Erase → choose "MS-DOS (FAT)" as the format (this is FAT32 for cards in this size range) → Erase.

For a card larger than 32 GB, neither OS's built-in formatter will offer FAT32 — Windows hides the option, and Disk Utility defaults you to exFAT. Forcing FAT32 onto a 64 GB+ card requires a third-party FAT32 formatting utility (there are several free ones for both Windows and macOS; we're not naming a specific tool or version here since Marauder's own FAQ caps supported capacity at 32 GB regardless). The simpler and more reliable path is just to use a card that's 32 GB or smaller in the first place — wardrive logs are lightweight CSV text, so there's no capacity reason to reach for a large card.

"SD card not detected" / mount failed

If Marauder reports the card isn't detected or won't mount, work through this in order:

  • Confirm the filesystem. Reformat to FAT32 (not exFAT, not NTFS) even if the card "looks" fine on a computer.
  • Confirm the size. If it's a 64 GB+ SDXC card, it's outside Marauder's supported range no matter how it's formatted.
  • Reseat the card. Push it fully into the slot; a card that isn't seated flush won't make reliable contact.
  • Check the contacts. Dust, lint, or corrosion on the gold contacts (on either the card or the slot) causes intermittent detection.
  • Try a different card. Individual cards and individual card slots both fail — swapping one variable at a time isolates which side is the problem.
  • Check the wiring, if applicable. On devboard setups where the SD reader is an add-on connected by jumper wires, a loose wire reads identically to "SD card not detected."

These are documented, ongoing reports, not isolated incidents: issue #227 and issue #95 on Marauder's GitHub both track SD card initialization/mount failures. For the fuller wardrive troubleshooting flow beyond just the SD card, see our ESP32 Marauder wardrive troubleshooting guide.

An honest 2026 note: Formatting to FAT32 and staying under 32 GB fixes the majority of reported cases — but not all of them. SD init/mount failures show up across different firmware builds and hardware revisions in Marauder's issue tracker, which points to at least some of these being driver-level regressions, not purely a "wrong card" problem. If a correctly-sized, correctly-formatted card still won't mount, that's a known open class of bug, not user error you should keep chasing indefinitely.

Onboard vs external SD

On a stock Flipper Zero WiFi Dev Board or a DIY breakout, the SD reader is often a separate module wired in over jumper leads or a header. That's one more physical connection that can work loose from handling, pocket carry, or a drop — and a loose SD connection looks exactly like "SD card not detected" from the firmware's point of view.

A board with the microSD slot soldered onto the PCB removes that one wiring point. Scout Lite ships this way: onboard microSD, no jumper wires, no external holder to jostle loose in the field. To be clear about what that does and doesn't fix — it eliminates a physical/wiring failure point. It does not make Scout Lite immune to the firmware-layer SD behavior described above; Scout Lite runs the same ESP32 Marauder firmware, so issues like #227 and #95 are software-side and can in principle affect any device running that build.

Scout Lite: board microSD, no wiring to work loose

Ships preloaded with ESP32 Marauder and a soldered-on microSD slot — one less connection point than a jumper-wired SD reader. Hard-soldered Quectel L86-M33 GPS too, so there's no pin mapping to set up before your first wardrive.

Get the Scout Lite →
Read the setup guide →

FAQ

What size SD card does ESP32 Marauder need?
Marauder's official FAQ specifies a microSD card of 32 GB or smaller, formatted FAT32. Larger SDXC cards (64 GB, 128 GB, 256 GB) ship exFAT by default and are not reliably supported — expect mount failures or corrupted wardrive logs. A 16 GB or 32 GB card is plenty for CSV wardrive logs.
Why is my SD card not detected on Marauder?
The most common cause is a card larger than 32 GB or formatted exFAT/NTFS instead of FAT32 — reformat it first. If a 32 GB-or-smaller FAT32 card still isn't detected, reseat the card, check the gold contacts for dirt or wear, and try a different card; GitHub issues #227 and #95 document SD init/mount failures that aren't always fixed by reformatting alone.
Does Marauder support exFAT or 64GB+ SD cards?
No. The official Marauder FAQ specifies two conditions together: 32 GB or smaller, and FAT32. A 64 GB+ SDXC card fails the size condition even if you force-format it to FAT32 with a third-party tool, so it falls outside what Marauder officially supports. Stick to a 32 GB or smaller card formatted FAT32.
Does the Scout Lite have onboard SD storage?
Yes. Scout Lite ships with an onboard microSD slot soldered to the board, so there's no jumper wire or external card holder to work loose. It still runs ESP32 Marauder firmware, so the same firmware-layer SD behavior documented in Marauder's GitHub issues can still apply — the onboard slot only removes one physical connection point, not firmware-level SD bugs.

Sources & further reading (verified 2026-08-03): Marauder wiki — SD card FAQ (32GB / FAT32 requirement); Marauder GitHub issue #227 — SD card not detected; Marauder GitHub issue #95 — SD mount failure; Marauder wiki — Wardrive mode.

For authorized security testing and education only. Test only networks and devices you own or have explicit written permission to test. You are responsible for compliance with all applicable laws and radio regulations (e.g. FCC Part 15 in the US). "Flipper Zero" and "ESP32 Marauder" are referenced for compatibility and comparison; PINGEQUA is independent and not affiliated with or endorsed by their respective owners.

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