[FS#1075] xiaomi mini hardware/power issues

[LEDE Bugs]

The following task has a new comment added:

FS#1075 - xiaomi mini hardware/power issues
User who did this - psyborg55 (psyborg55)

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of course that was first measuring. another attempts gave 0V on both amps on the pins 1-2 measured first time! which makes no sense and is completely retarded regardless if powered from wall or battery. 

another pin measurement 1-3 also show lower voltage on LNA1 about 1.84V while LNA0 is 2.25V (LNA pinout can be found in http://www.mouser.com/ds/2/196/bf776-90370.pdf)

so i took multimeter just to find out C558 between switch and amp had 0 ohm resistance while same capacitor on chain0 had some resistance, of course unsoldered it and tried to short pads which completely confused dumb mediatek chip that showed 20dB less rssi so i soldered the thing back and the chip is stuck calculating rssi from chain0 only - my 2T2R test has now same values as other 3 tests. there was no performance drop, but that should still be verified using mtk driver.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1075#comment3692