Firmware file

Official firmware files

Official firmware files is not publicly available.

The NIIMBOT app sends the printer model and version to the API server. If an update is available, the server can provide a URL for downloading the firmware.

This way the bunch of official firmware files was collected here: https://fw.niim.blue/

Structure of firmware file

Applies to new firmware files starting with 0x18 byte. Byte order is little endian.

Offset	Length	Example	Description
0x00	1	`18`	Signature
0x01	3	`99 BE 4A`	Some random data, threat as zero when calculating header CRC
0x04	4	`74 DF 01 00`	Length of firmware data
0x08	4	`46 7A AC 3E`	CRC32 of firmware data
0x0C	4	`00 00 00 00`	Reserved
0x10	4	`00 00 00 00`	Reserved
0x14	2	`35 01`	Firmware Version
0x16	2	`10 03`	Device model ID
0x18	4	`FC E8 23 77`	CRC32 of previous data where bytes at 0x01-0x03 threated as zero
0x1C	?	`00 51 03 ..`	Firmware data

ImHex pattern

Firmware header editor (works in browser)

Structure of compressed firmware file

First seen in B1 PRO. Compressed with DEFLATE algorithm.

Offset	Length	Example	Description
`0x00`	1	`18`	Signature
`0x01`	3	`99 BE 4A`	Some random data, treated as zero when calculating header CRC
`0x04`	4	`XX XX XX XX`	Length of compressed payload
`0x08`	4	`XX XX XX XX`	CRC32 of compressed payload
`0x0C`	4	`00 00 00 00`	Reserved
`0x10`	4	`00 00 00 00`	Reserved
`0x14`	2	`35 01`	Firmware Version
`0x16`	2	`10 03`	Device model ID
`0x18`	4	`XX XX XX XX`	CRC32 of header `0x00-0x17`, with bytes `0x01-0x03` treated as zero
`0x1C`	4	`XX XX XX XX`	Uncompressed firmware size
`0x20`	4	`00 80 00 00`	Compression block size, normally `0x8000` (32768)
`0x24`	4	`XX XX XX XX`	Block 0 record length = `4 + compressed size`
`0x28`	4	`00 80 00 00`	Block 0 uncompressed size
`0x2C`	?	`...`	Block 0 raw DEFLATE data
`...`	4	`XX XX XX XX`	Next block record length = `4 + compressed size`
`...`	4	`XX XX XX XX`	Next block uncompressed size
`...`	?	`...`	Next block raw DEFLATE data
`...`	...	...	Repeated until entire firmware is represented

Firmware repacker (works in browser)

Firmware structure and compression algorithm was reverse engineered by mode01.