Stacking a Cisco 3750x into a plain 3750 stack

I’ve had all kinds of problems with this tonight. Luckily, none have affected the operating stack which is a pair of 3750’s. Not E’s or V2’s but original 3750’s. I’m trying to add a 3750X which is supposed to work just fine. I’ve done all kinds of things including about 10 different versions of 12.2.55 to no avail. I had another problem with the 3750x being LANBASE so I got a temp license (which I’ll have to pay for) for the IPBASE image. The versions, license levels and all of that are exactly the same. Then I stumble across this post:

I recently stacked 3750x-48pf-s running ip base with 3750v2-24. I originally attempted to use 12.2(55) but the stack failed to initialize, almost like the stack ports on the 3750x were err-disabling.

After some hair pulling I downgraded to 12.2(53) ( lowest version supported by both) and it did a full EEPROM rewrite on the 3750x. The stacking worked properly after that.

That is exactly my problem!

I’m currently installing 12.2(53) and it’s running a lengthy microcode update. I mean lengthy. This better work!

Update: Downgrading all of the switches to 12.2(53) worked although the new 3750x decided to be master and wiped out my config. Good thing we had a backup.

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