Intel HEX and S-Record inspector

You need to check a firmware .hex or .srec file before flashing: checksums, address gaps and the image CRC. Parses Intel HEX and Motorola S-records, validates every record checksum, maps segments, computes the image CRC-32 and converts to .bin with 0xFF gap fill.

Open the calculator in EM·LINKBelow is a worked example. The working calculator runs free in EM·LINK.

Worked example

Example inputs

sensor-node-v1.2.hex4520 B
Intel HEX (detected)▾
FFhex
First to last address▾

Example result

Record checksums105 of 105 valid

Two segments with a 520 byte gap, filled with 0xFF in the .bin.

PartStartEndBytes
Segment 108000000080005F71528
Gap080005F8080007FF520
Segment 2080008000800085F96

Image CRC-32 0xDD4BFF23 over 2144 bytes. Start address 0x08000189.

Your file is parsed in your browser. Nothing is uploaded.

Run it with your own values

The working calculator is Intel HEX / SREC Inspector in EM·LINK, our free browser tool. The button opens it directly.

Open in EM·LINK

How to read the result

Extended address records are tracked, so images that cross a 64 KB boundary decode to the right absolute addresses.

Gap fill uses 0xFF to match erased flash, so the .bin matches what ends up in the chip.

How this is calculated

Every record carries its own checksum. Extended address records (type 04) set the upper 16 bits, so data records map to absolute flash addresses.

:LLAAAATT[DD...]CC Intel HEX: sum of all bytes mod 256 = 0 S-record: sum of all bytes mod 256 = 0xFF Type 04 sets the upper 16 address bits
:100000000050002089010008FD2992936477103781startcount 16addresstype, data16 data byteschecksumSum of every byte before the checksum is 0x47F. Low byte 0x7F, two's complement 0x81.

The full derivation, step by step, is in the EM·LINK documentation.

Calculated per common engineering practice (the Intel HEX and Motorola S-record file formats). These tools are an engineering aid, not a certification.

Next step

Shipping hundreds of units? Get OTA updates and remote config without building it yourself.

Common questions

How do I convert Intel HEX to bin?

Drop the file in. The tool maps segments and exports a .bin with 0xFF gap fill.

How is the Intel HEX checksum calculated?

Two's complement of the sum of all preceding bytes on the line.

Is my firmware uploaded anywhere?

No. The file is parsed in your browser only.