Optiboot on arduino Nano

Hi Given that the arduino Uno and arduino Nano have the same H.W., I am wondering whether it is possible to install Uno's bootloader "optiboot" on Nano, since Nano's bootloader has problem with the watchdog timer while Uno works just fine with it. I have seen many posts that talk about installing the device's default bootloader (i.e., optiboot for uno). But how about optiboot on Nano or promini? any hidden stuff that I should account for, any ideas, concerns, notes will be highly appreciated.

Also a final note, why the Nano and Promini are not using the optiboot as their bootloader? it seems to me better than what they are using. Any clarification on that?

Thx in advance. Mike

I bootload all my 328P chips as Uno, makes it easy to only have to remember one board type for 328Ps, one for 1284Ps (I use Bobuino as my 1284P board type), and one for 2560s (Mega).

The Nano and Pro Mini designs were before the Uno, and based on Duemilanove. So they continue to use the Duemilanove bootloader. If they sold them with the Uno bootloader on them, they would probably have to call them something else so people wouldn't get them, plug them in, and have difficulty uploading to them, and then complain to the seller. There's nothing wrong with the end user burning the Uno bootloader on them and just calling them Uno Jr. The 8MHz Pro Mini you may need to run at a lower baud rate.

So in short, there is no difference as regards hardware (noting that you need to use the appropriate driver for whatever USB interface chip is present) between Duemilanove, Nano and UNO that limits what bootloader you employ. You can and indeed, should load a Nano - or a Duemilanove - with Optiboot.

Now what annoys me is the frequent marketing of clones as "UNO" or "UNO R3" when in fact, they are anything but a UNO R3 and are actually Duemilanove clones only as they lack the 16U2. Again, if they contain the Optiboot loader, they can admittedly be programmed as a "UNO" and perhaps that is all that matters to the uninitiated, but completely lack the 16U2 functionality.

Thank you guys, your answers made it all clear.