There never was a free version of IDA Pro that supports (local) decompilation of any sort. The current IDA Pro free version supports "cloud-based" decompilation - that means your IDA copy uploads the function to decompile to a cloud service, and that cloud service responds with a decompilation of that function. This version of IDA does not contain support for loading LE/LX executables.

If you are satisfied with disassembly instead of decompilation, the generally recommended free IDA version is 5.0. This version is still legally obtainable at https://www.scummvm.org/news/20180331/ for example.

Thanks for the comment and the link. I see, but somewhere on the internet I've read that IDA Pro Free ver. 4.3 will be OK for my purposes (just dissassembly is fine too), but I'm wondering if it's the last (newest) of 4.x versions? And I can't even find this free version 4.3 anywhere for download.

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analog_programmer wrote on 2023-12-03, 17:41:

Thanks for the comment and the link. I see, but somewhere on the internet I've read that IDA Pro Free ver. 4.3 will be OK for my purposes (just dissassembly is fine too), but I'm wondering if it's the last (newest) of 4.x versions? And I can't even find this free version 4.3 anywhere for download.

IDA Freeware 5.0 (offcial download approved by the IDA developers: https://www.scummvm.org/news/20180331/) is the better choice compared to 4.3 but i don't know/think if it contains LE/LX (DOS4GW) support

the commercial version - up to the latest 8.3 contains full DOS support with LE/LX support - but there is no 16bit decompiler available, even not with the commercial license

llm wrote on 2023-12-03, 19:23:

IDA Freeware 5.0 (offcial download approved by the IDA developers: https://www.scummvm.org/news/20180331/) is the better choice compared to 4.3 but i don't know/think if it contains LE/LX (DOS4GW) support

the commercial version - up to the latest 8.3 contains full DOS support with LE/LX support - but there is no 16bit decompiler available, even not with the commercial license

Yeah. And all this leads me to IDA Pro Free ver. 4.xx., but I can't find any of these 4.xx versions for free downloading.

analog_programmer wrote on 2023-12-03, 19:48:

llm wrote on 2023-12-03, 19:23:

IDA Freeware 5.0 (offcial download approved by the IDA developers: https://www.scummvm.org/news/20180331/) is the better choice compared to 4.3 but i don't know/think if it contains LE/LX (DOS4GW) support

the commercial version - up to the latest 8.3 contains full DOS support with LE/LX support - but there is no 16bit decompiler available, even not with the commercial license

Yeah. And all this leads me to IDA Pro Free ver. 4.xx., but I can't find any of these 4.xx versions for free downloading.

I found IDA Freeware 4.3 at https://www.sac.sk/download/utilprog/freida43.exe , but it doesn't include the loader for LE executables. IDA Freeware 4.9 and IDA Freeware 5.0 also don't.

On the other hand, IDA 4.1 freeware, for example at https://sourceforge.net/projects/hawk800/files/Disassembly/ does include the LE loader, but this version only includes the Windows console application, which stubbornly insists on resizing the console window to 80x25 (the DOS IDA version was better, I successfully used it in 100x37 text mode). But not all is lost: You can load a LE/LX exectuable using IDA Freeware 4.1 and then continue working in IDA Freeware 5.0

mkarcher wrote on 2023-12-03, 23:29:

I found IDA Freeware 4.3 at https://www.sac.sk/download/utilprog/freida43.exe , but it doesn't include the loader for LE executables. IDA Freeware 4.9 and IDA Freeware 5.0 also don't.

On the other hand, IDA 4.1 freeware, for example at https://sourceforge.net/projects/hawk800/files/Disassembly/ does include the LE loader, but this version only includes the Windows console application, which stubbornly insists on resizing the console window to 80x25 (the DOS IDA version was better, I successfully used it in 100x37 text mode). But not all is lost: You can load a LE/LX exectuable using IDA Freeware 4.1 and then continue working in IDA Freeware 5.0

Thank you very much for the links and the clarifications! So, I'll try this combo IDA Pro Free ver.4.1 + ver.5.0.

Ok, maybe this is a stupid question, but since I'm not using Windows for daily driver OS, do these IDA Free versions 4.1 and 5.0 work with Wine or I have to use true Windows environment? There is a free version for Linux available on official site, but it is version 8.3 that I can't use for 16 bit DOS executables.

analog_programmer wrote on 2023-12-04, 13:51:

Ok, maybe this is a stupid question, but since I'm not using Windows for daily driver OS, do these IDA Free versions 4.1 and 5.0 work with Wine or I have to use true Windows environment? There is a free version for Linux available on official site, but it is version 8.3 that I can't use for 16 bit DOS executables.

In my experience, those old IDA versions work good enough in Wine. Wine's AppDb lists IDA Free 5.0 only at "silver" level, because the "preview tooltip" (hovering over a jump instruction is supposed to show a popup with the instructions at the jump target) does not work (see https://appdb.winehq.org/objectManager.php?sC … rsion&iId=23368). This is just a minor inconvenience for most people, and using the mouse wheel to change the popup size makes the text visible, see https://bugs.winehq.org/show_bug.cgi?id=16183 .

mkarcher wrote on 2023-12-04, 20:20:

In my experience, those old IDA versions work good enough in Wine. Wine's AppDb lists IDA Free 5.0 only at "silver" level, because the "preview tooltip" (hovering over a jump instruction is supposed to show a popup with the instructions at the jump target) does not work (see https://appdb.winehq.org/objectManager.php?sC … rsion&iId=23368). This is just a minor inconvenience for most people, and using the mouse wheel to change the popup size makes the text visible, see https://bugs.winehq.org/show_bug.cgi?id=16183 .

This looks promising. Thanks for the information about Wine compatibility.

llm wrote on 2023-12-03, 19:23:

IDA Freeware 5.0 (offcial download approved by the IDA developers: https://www.scummvm.org/news/20180331/) is the better choice compared to 4.3 but i don't know/think if it contains LE/LX (DOS4GW) support

It turned out that IDA Free version 4.3 also supports LE/LX format DOS executables and it's much faster and convenient than free version 4.1. Tried them both with Wine - no problems so far. Now I'll try free version 5.0 with Wine.

P.S. Version 5.0 also works fine with Wine. Version 4.1 gives me better assembly code than 4.3, so I'm using combination of versions 4.1 and 5.0.

The job's done. Thanks to everyone who commented for the shared information and links.