Router 1841 "Wrong software for this machine"

[David H Lee]

Hello all! I'm currently dealing with one router, then I caused problem again. I tried to check if one Compact Flash drive is readable on cisco router, so I took old one out of 1841, then put 2811's CF( one that I'm having trouble with), then 1841 act weird, so I put the old one back in, then tried to reboot. However, it's constantly saying "wrong software for this machine". what I am I supposed to do? any clue? sorry for causing problems. thank you once again! 

[chrihussey]

So it's not booting with and IOS at all? I suspect it ends up in rommon mode. If so you should be able to check what is on the flash and if necessary load new code using the TFTPDNLD utility. The attached link should provide some guidance:

https://www.cisco.com/c/en/us/td/docs/routers/access/1800/1841/software/configuration/guide/sw/b_rommon.html

Hope this helps