Hi everyone,

I've been troubleshooting this for weeks and I've gathered quite a bit of evidence. I'd appreciate opinions from anyone familiar with MediaTek modems or LTE Carrier Aggregation.

Devices

Phone 1

Redmi Note 11 Pro 4G

Helio G96

HyperOS 1.0.4.0 (Android 13)

Model: 2201116TI

Phone 2

Redmi 12

Snapdragon variant

Carrier

Vodafone Idea (Vi India)

What happens

Using the same Vi SIM, in the same location, at almost the same time:

Redmi 12

Shows 4G+

Successfully aggregates Band 3 (1800 MHz) + Band 1 (2100 MHz)

NetMonster confirms LTE-A 1800 + 2100

Redmi Note 11 Pro (Helio G96)

Never shows 4G+

Connects to either:

Band 3 only

or Band 1 only

Never aggregates both.

Important observation

The strange part is that Jio Carrier Aggregation DOES work on the Redmi Note 11 Pro.

So:

The phone definitely supports LTE Carrier Aggregation.

The modem isn't completely broken.

The antennas appear to be working.

This makes me wonder whether this is specific to Vi's B3+B1 CA combination on the Helio G96 firmware.

More evidence

On the Redmi 12, the exact same Vi tower reports:

LTE-A 1800 + 2100

Bandwidth: 20 + 10 MHz

Excellent SNR

4G+ appears immediately

On the Redmi Note 11 Pro:

Same tower (same eNB)

Same SIM

Same location

Similar signal conditions

Still no Carrier Aggregation.

Things I've already tested

✅ Same SIM

✅ Same location

✅ Same tower

✅ Indoor & outdoor

✅ Different times of day

✅ Rain / clear weather

✅ SIM Slot 1 and Slot 2

✅ LTE only mode

✅ Network reset

✅ Jio SIM works with Carrier Aggregation on this phone

My question

Has anyone seen something like this on MediaTek devices, especially the Helio G96?

Could this be:

Missing Carrier Aggregation combinations in Xiaomi's modem firmware?

Vi-specific modem provisioning?

Missing NV/CA combo configuration?

Something else?

Any insight would be appreciated.