It seems very unlikely that the device is that similar. It might look the same but have completely different hardware inside.
If the CyanogenMod i9300 zip works on your device, then Replicant will probably work as well. Now I doubt anyone has tested Replicant on your device yet, so you may have more luck finding out about CyangogenMod.

> It might look the same but have completely different hardware inside.

Indeed. Compare http://www.phonearena.com/phones/Samsung-Galaxy-S3-Neo_id8584 and http://www.phonearena.com/phones/Samsung-Galaxy-S-III_id6330, and you'll see that the system chip is said to be a "Qualcomm Snapdragon 400 8226", whereas it was a "Samsung Exynos 4 (4412)" in the original Galaxy S 3.

In TargetsEvaluation the other device with a Qualcomm Snapdragon is marked as "Really BAD". Does the same evaluation hold for all devices with a Qualcomm Snapdragon?

Does the same evaluation hold for all devices with a Qualcomm Snapdragon?

Most likely yes.

I've read in a forum a few months ago, that there isn't any compatible (CWM) recovery for that device.
So there could start the trouble...

Thanks. I somehow got hold of a i9300 through ebay.

Galaxy S3 Neo variants¶

• GT-I9300I - http://www.samsung.com/levant/consumer/mobile-devices/smartphones/galaxy-s/GT-I9300MBIMID/
• GT-I9301I - http://www.samsung.com/africa_en/support/model/GT-I9301MBIXFE
• GT-I9301Q

• GT-I9300I has: Dual SIM

CyanogenMod and LineageOS ROMs for Galaxy S3 Neo¶

• CyanogenMod 12 (Apr 23, 2015)
• CyanogenMod 12.1 (May 18, 2015)
• CyanogenMod 13 (Jul 30, 2016)
• LineageOS 13 (Feb 2, 2017)
• LineageOS 14.1 (Sep 24, 2017)

Compare Galaxy S3 (i9300) vs. Galaxy S3 Neo (i9300i)¶

https://www.gsmarena.com/compare.php3?idPhone1=4238&idPhone2=6289

• Galaxy S3: http://www.samsung.com/in/support/model/GT-I9300RWDSLK
• Galaxy S3 Neo: http://www.samsung.com/levant/consumer/mobile-devices/smartphones/galaxy-s/GT-I9300MBIMID/

Release date¶

• Galaxy S3: May 2012
• Galaxy S3 Neo: April 2014

OS¶

• Galaxy S3: Android 4.0.4 (Ice Cream Sandwich), 4.3 (Jelly Bean)
• Galaxy S3 Neo: Android 4.3 (Jelly Bean), upgradable to 4.4.4 (KitKat)

Chipset¶

• Galaxy S3: "Average Benchmarks Samsung Exynos 4412 Quad → 100%"
• Galaxy S3 Neo: "Average Benchmarks Qualcomm Snapdragon 400 MSM8226 → 97%"

CPU¶

• Galaxy S3: Quad-core 1.4 GHz Cortex-A9
• Galaxy S3 Neo: Quad-core 1.2 or 1.4 GHz Cortex-A7

RAM¶

• Galaxy S3: 16/32/64 GB, 1 GB RAM
• Galaxy S3 Neo: 16 GB, 1.5 GB RAM

SIM¶

• Galaxy S3: Micro-SIM
• Galaxy S3 Neo: Dual SIM (Micro-SIM, dual stand-by)

WLAN¶

• Galaxy S3: Wi-Fi 802.11 a/b/g/n, dual-band, Wi-Fi Direct, DLNA, hotspot
• Galaxy S3 Neo: Wi-Fi 802.11 a/b/g/n, dual-band, Wi-Fi Direct, hotspot

Battery¶

Stand-by¶

• Galaxy S3: Up to 590 h (2G) / Up to 790 h (3G)
• Galaxy S3 Neo: Up to 330 h (2G) / Up to 340 h (3G)

Talk time¶

• Galaxy S3: Up to 21 h 40 min (2G) / Up to 11 h 40 min (3G)
• Galaxy S3 Neo: Up to 14 h (3G)

Summary¶

• Battery: 56% better
• WLAN: DLNA

• RAM: 33% better
• SIM: Dual SIM
• OS: Upgradable to Android 4.4.4

There are now official LineageOS 16.0 images available for the i9301:

https://download.lineageos.org/s3ve3gjv
https://download.lineageos.org/s3ve3gxx

They work exceptionally well (1.5 GB of RAM are so much better than 1 GB), but the Qualcomm SoC problem of course remains.

Seams like S3neo(I9301) uses a chipset family supported and used by
lk2nd. Ounce replicant 11 is released might be smart to look into this https://github.com/msm8916-mainline/lk2nd.

So that might be a posibility.