What is a .UF2 file?
UF2 lets you flash a microcontroller by dragging the file onto a USB drive. Created by Microsoft.
- Did you know
- Microsoft made UF2 for MakeCode so beginners could flash boards with a simple drag-and-drop.
- A UF2 file is a sequence of self-contained 512-byte blocks, each carrying up to 476 bytes of payload plus a header and a trailing magic number.
- The fixed block size aligns with USB mass-storage writes, so a microcontroller never receives a half-written file when you drag one across.
- What Analyser reads
- Inspect virtual-machine descriptors (VMware .vmx, VirtualBox .vbox, OVF/OVA), disc images (Nero .nrg, Alcohol .mds/.mdf, CloneCD), embedded firmware (Intel HEX, Motorola S-record, UF2, ELF/AXF, Device Tree Blobs, U-Boot uImage), partition tables (MBR/GPT with GUIDs), Linux filesystem superblocks (ext2/3/4, SquashFS, cramfs, romfs) and Windows imaging (WIM/ESD) - reading headers directly, no upload.
- Depth of analysis
- .UF2 is an identification-grade format: Analyser recognises it from its bytes and decodes the header metadata it carries, rather than opening it in a full viewer. Formats that do get a full viewer are marked "Full" on the formats page.
- Open a .UF2 file
- Drag a .UF2 file onto the Analyser home page (or tap to pick one). It is identified entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.