Default [Q] Need help unrooting a Samsung S2 GT-I9100

B"H

I probably too eagerly installed Kit Kat onto a previously functional I9100 (it was running CM 10.2 prior to this).

Now,
1. A lot of the Google apps crash, repeatedly;
a. The keyboard will not work, anywhere. Keeps crashing.
b. Gmail will not run or sync.
c. A host of other first-world problems.
2. CWM recovery does not see the SD card and also does not see the internal memory, only a couple of mystery directories
3. Odin does not see the phone.

I would like to either re-flash the phone to a previous version of CM OR unroot it and flash the latest 4.1 from Samsung. I have the ROMS for either option, I just have not yet gotten the phone to "see" them.

UPDATE:
I ran root checker on it. Here are the results:
BOARD Smdk4210
BOOTLOADER unknown
BRAND Samsung
CPU_ABI armeabi-v7a
CPU_ABI2 armeabi
DEVICE GT-I9100
DISPLAY cm_i9100-userdebug 4.4 KRT16M 231e38def4 test-keys
FINGERPRINT Samsung/GT-I9100/GT-I9100:4.0.3/IML74K/XXLPQ:user/release-keys
HARDWARE smdk4210
HOST bestcombats.ru
ID KRT16M
MANUFACTURER samsung
MODEL GT-I9100
PRODUCT GT-I9100
RADIO unknown
SERIAL unknown
TAGS test-keys
TYPE userdebug
UNKNOWN unknown
USER pavelk

In case the above reveals any clues as to the source of the problem(s)

If anyone knows what I might do, please let me know.

Thanks.