I've installed various versions of RouterOS (inclusing v4.2) onto compact flash cards before. I just bought a pair of 4GB SanDisk Ultra II compact flash cards. When I installed RouterOS v4.2 on them and rebooted, I got a BIOS error stating that "Operating System Not Found".

This is the same computer, the same CD ROM drive, and the same Mikrotik RouterOS v4.2 install disk. The only difference is the compact flash cards themselves. Previous installations that I've done used smaller cars as large as 1GB or 2GB. ?This is the first time that I've tried with a 4GB card.

more likely its a motherboard issue, not the CF. what setup are you using?

I'm facing a similar issue but using a 8GB Kingston Elite Pro Compact Flash.

I cannot install RouterOS by network nor by USB.


I tried 3 different card readers, 2 different host operating systems, 2 different target computers and 2 different pieces of CF (same model).

more likely its a motherboard issue, not the CF. what setup are you using?

It's a standard SuperMicro system with an IDE CD-ROM drive, and a SATA compact flash adapter. I've used this exact same system to install RouterOS to other, smaller CF cards several times. I've made no BIOS changes other than switching the boot order from CD to compact flash, and vice-versa.

which supermicro mobo? there was a handful that needed beta bioses to make them work right. The PDSBM comes to mind. The problem comes in with certain CF cards being presented with DMA, 32 bit transfers, etc.

I'm facing a similar issue but using a 8GB Kingston Elite Pro Compact Flash.

I cannot install RouterOS by network nor by USB.


I tried 3 different card readers, 2 different host operating systems, 2 different target computers and 2 different pieces of CF (same model).

I went to Frys and bought the slowest, cheapest, crappiest Kingston 4GB compact flash card that they had. It worked fine. I believe that user changeip was right about the drive performance settings needing to be changed. I did play around with the bios settings for the compact flash on my supermicro a little bit, but I decided that I was better off just using a plain old CF card instead.

As a practical matter, I don't want my staff to have to remember that such-and-such type of flash memory requires this-and-that performance settings in the BIOS. So we'll just stick with the slow flash cards for as long as we can.

Thank you to changeip for your advice. I suspect that one day companies will stop making the slow flash cards and we'll need to work on the drive performance settings to make them work properly. At least now I know in which direction to go when that time comes.

Keep in mind that many of those cards have less than 100,000 writes on them. I have seen some cards spec out at 10,000, for camera images etc, that maybe fine, but for an OS that could be running for years, might be bad. I would also always recommend products listed in the HCL on mikrotiks site as well.