Dial # # 3646633# # (engineer mode) go to band mode disable bands 4 and 66 , there wont be service.
It’s אפשר לברר check for yourself .
(Fyi most places in us have bands 4 and 66, the fact that if works doesn’t mean it has all the US bands)
your right. anyone idea why this is
Thanks. That’s what I thought.
Probably hardware
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Here is some clarity on the band issue, after some research:
The F30 (and flashed F21s) support the following bands, according to the original post on xda by CatStoleTheCrown:
2, 4, 12, 13, 17, 66, 71
In the US these are the major bands, with the exception of band 5, which is the only primary band used by all the major carriers that is not supported by the F30.
Here is the breakdown of the US bands:
2 Att, T-Mobile, US Cellular, Verizon (qin supported)
4 Att, T-Mobile, US Cellular, Verizon (qin supported)
5 Att, T-Mobile, US Cellular, Verizon (qin NOT supported)
12 Att, T-Mobile, US Cellular (qin supported)
13 Verizon (qin supported)
14 Att (qin NOT supported)
17 Att (qin supported)
25 Sprint, Boost (qin NOT supported)
26 Boost (qin NOT supported)
29 Att (qin NOT supported)
30 Att, Sprint (qin NOT supported)
41 Sprint, Boost (qin NOT supported)
66 Att, T-Mobile, Verizon (qin supported)
71 Att (qin supported)
I would credit the source for the US band list, but I forgot where I copied it from.
At&t only backup bands not supported by qin: 14, 29, 30
Sprint/boost mobile bands not supported: 25, 26, 30, 41
As you can see, the only major US band NOT supported by qin is band 5.
Maybe some other devs can play around with Maui Meta or some other tools to flash band 5?
I think that its less simple than flipping a bit mask, as it used to be in older versions of android, giving the little research that I have done. It is likely that this will require serious modification of the telephony/modem firmware. However, adding band 5 to the qin (most likely the hardware CAN support, its similiar to other supported bands in terms of wavelength/frequency range) would be a serious addition and could probably be considered “complete” US support.
I was told that the f30 has slightly different radio hardware than the f21. True?
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I can’t confirm, I never opened one up. If the hardware is different the modem chip should have a different variant id printed on it.
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Either way, if the F21 hardware supports the same bands as the F30, it should also support band 5. However, an important note: Just because a band is enabled at the software level, does not mean it can work at the hardware level. The hardware must support the band in addition to it being enabled in the firmware. If it is enabled in the firmware, but not supported by the hardware - you still won’t get service on that band. Even worse, it may break your existing service, because the phone will keep trying to switch to that band when the tower tells it that it is available, and you will lose service for a couple seconds until the phone realizes it can’t get a signal and switches back. This will keep happening, because the phone won’t learn to avoid the band.
Not true go to engineer mode (star# Star#3646633# Star # Star) on a f21 go to band mode disable bands 4,66
u will lose service, as i have repeated many times the f21 even with flashed with all bands only works on bands 4 and 66
Thanks! That is good to know.
According to this post on XDA, the stock firmware supports these bands:
1, 3, 5, 7, 8, 20, 28, 34, 38, 39, 40, 41.
The F30 (and Flashed F21s) have firmware support for these bands:
2, 4, 12, 13, 17, 66, 71.
According to @sb123, the F21 only has hardware support for bands 4 and 66 of the above F30 enabled bands. I do not know if the F30 hardware is different, or if it too only has hardware support for those two bands. We also don’t know how many of the enabled stock bands are actually supported by the hardware.
Bands 4 and 66 both run on 1700MHz frequencies for the uplink and 2100MHz frequencies for the downlink, according to Wikipedia. If the Qin hardware only supports these frequency ranges, it would make sense that it can only use bands 4 and 6.
Band 1 downlink is included in band 66’s range, but it’s uplink is in the 1900MHz range. Band 3 has a very similiar uplink to band 4 and is almost the same as band 66, but its downlink is in the 1800MHZ spectrum. In summary, bands 3, 4, and 66 are the only ones that uplink in 1700MHz, while bands 1, 4, 65, 66 are the only ones that downlink in 2100MHz. Bands 4 and 66 are the only ones that do both.
We only know for a fact that the Qin F21 radio supports uplink in 1700MHz and downlink in 2100MHz. There absolutely must be more support though, because none of the stock supported bands fall into this category. Even bands 1 and 3, supported by stock, only do one of the above, either uplink on 1700MHz or downlink on 2100MHz. If the radio supported their uplinks and downlinks, it should also support band two which operates on similar frequencies.
The MT6761 (Helio A22) chip officially supports almost all LTE bands, for two simultaneous connections. However, the device manufacturer must install and RF front end (antennae and filters) to support this. Since the Qin is a single SIM device, we can assume that the RF front end only supports a single connection. Additionally, since it does not target the US, it won’t have antennae and filters for US bands, except where they cross over with international bands (as is the case with bands 4 and 6).
I think nailing down the exact supported frequencies will tell us which bands the radio can actually physically support. So here is a starting point: Anyone with an F30 or F21 can please open the cover and look for an FCC ID and post it here? (It may or may not have one, though legally the F30 should).
You can look for FCC internal device pics
Beat you to it! - That’s why I want the FCC ID. However, I probably won’t need the internal device pics once I get an FCC ID because it should display the frequencies in the FCC listing without me having to research the hardware.
I’ll send it to you later
I just opened an F30 and two F21s looking for an FCC ID, there was none. The Absolute only differences in the casing between the F30 and F21s:
- F30 is grey, F21 black or white.
- F30 says “CC F21 PRO US MAIN V2” on the inner casing beneath the battery. The F21 (3/32 and 4/64) says “CC F21 PRO2 E-A MAIN V1-1” instead.
- F30 battery says QIN F30 and battery specs in English. F21 has a megillah written in the battery in Chinese.
There is no visible FCC ID imprint or FCC compliance sticker (mandatory for radio communication devices sold in the US) on either the F21 or the F30.
I did not actually take it apart or remove the battery, just the back cover, so I did not get to see the antennae or RF modules. If they are identifiable and labeled, they may get us somewhere, if someone has the patience to take one apart. Technically, since the F30 targets the US market (“CC F21 PRO US MAIN V2”) it should have an FCC ID, but that doesn’t mean that it does. If you find anything, please share!
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I found that through this
Excellent work!
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Without getting too technical, this confirms that the F30 radio is designed specifically for North America, using chips built specifically to support North American LTE frequencies. What remains to be seen is if we can get this exact photo from an F21 - if anyone has the patience to pull one apart and upload a photo. Then we can compare the chips.
MT6761V (The phone’s “brain” - among everything else, it also commands the radio what to do.)
MT6177MV - The “radio” transceiver chip. Takes orders from MT6761V. This chip can talk and receive basically all LTE frequencies - provided it is connected to the proper antennae (called RFFE, the RF Front End).
SMMI S5643-51 - Global PA, part of the RF Front End for LTE Bands 1/2/3/4/5/7/8/12/13/17/20/25/26/28/66/71.
SMMI S2916-51 - Highband PA, part of RF Front End for the higher frequency bands, 34/38/39/40/41. (41 is used by T-Mobile).
Just because this hardware supports all these bands halfway through the RF Front end, it still doesn’t mean they’ll work. There is one more thing the bands need: Filters and Duplexers. These decide what frequencies reach the PAs from the antennae. So even if the PA can process a specific frequency, it may not reach it due to lack of duplexer/filter config for those freqs. The little black boxes are most likely the duplexers, I can’t make out their markings in the photo, although it looks like korean or chinese. Some of them are supposed to have band numbers written on them. A hi-res photo of an F21 would be very helpful!
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Do you have an extra one in Lakewood
Would gladly do