Difference between non-US and US-version of firmware?

[Apachez-]

Looking at the firmware pages sometimes US-versions pops up, but not for every release.

Last week these two versions showed up which made me question whats the purpose but also what the difference would be?

Software release 5120.EI-4210G-4510G_5.20.R2221P01
bin-file: 13471972 bytes

Software release 5120.EI-4210G-4510G_5.20.R2221P01-US
bin-file: 13467013 bytes

Difference: 4959 less bytes in US-version.

Sure the US-version states that "Software built in the United States", but shouldnt the firmware files still be equal size and hash?

Or is the difference only that US-version contains NSA backdoors and such (or are there other differences in the code aswell)?

Another observation is that the bootloader (btm-file) seems to still be the same in both non-US vs US-version (same size and hash) - wouldnt the same apply for the bootloader if the "Software built in the United States" - that is that the bootloader size and hash would differ?

[MichaelM55]

[/sarcasm on]

Well, they removed the chinese code and added the US one. As the US spying part is way smaller than its chinese counterpart, the resulted US firmware is smaller than the chinese... Logical, right?

[/sarcasm off]

• Different compilers/compiler versions being used
• Different packaging, just unpack the *.bin files with e.g. 7zip and see what´s there

[Apachez-]

I doubt different libs/compiler would be used because that would render a whole new testperiod of the compiled firmware, not to mention the bugs the compiler itself can introduce.

Regarding open up in 7zip the 30.1MB bin file is just 1.4 MB "extend" file according to 7zip... so the content is obviously not being recognized by 7zip...