USB Mass Storage Explorer
Talk SCSI over USB Bulk-Only Transport: inspect capacity, partitions and file systems, and view, edit and write raw sectors. Also opens disk image files.
Browsers block WebUSB access to mass-storage interfaces (class 0x08). This works with devices that expose the Bulk-Only protocol under another class (e.g. 0xFF vendor-specific), or with Chrome started with --disable-webusb-security. The OS storage driver must also let go of the device (on Windows, swap it to WinUSB with Zadig). Disk image files work in any browser.
This browser doesn't support WebUSB (or the page isn't in a secure context). Use desktop Chrome or Edge, or open a disk image instead.
Device
Interface
LUN
The file stays in your browser. Edits are kept in memory; use Download modified image to save them.
Device
Partitions & file systems
Sector editor
LBA
Click a byte, then type hex digits (or text in the right-hand column). Arrows/PgUp/PgDn move, Tab switches columns, Ctrl+Z undoes.
Colored bytes are recognized structures; hover for a description. Edited bytes are red.
At cursor
Image dump
Back up anything before writing to it. Dumps are held in memory, so they are capped at 2 GiB.
Log