I have tried dfu restore with two cables (Apple charger cable and high quality usb-c display- & charging cable)
- target battery disconnected
- target battery disconnected, target power connected
- target battery connected
- target battery connected, target power connected

Same result always, apple configurator hangs on step "4/4 Installing System". Host machine is 2018 MacBook pro with most recent MacOS....

I managed to put device to dfu mode but both revive and restore actions fails. Device is titled as Apple controller in Apple configurator.

Progress bar stops at about 1/3 on step 4/4 Installing System.

Finally Apple configurator displays error message: "The system cannot be restore on this device. Gave up waiting for device transition from DFU state to DFU state. [com.apple.MobileDevice.MobileRestore - 0xFCA (4042)]"

I noticed that battery voltage raised from 10 to 11 when trying to restore. Apparently it is charging....

OK, here are the measurements:

P5VG3S_EN_DLY 0v
PPBUS_G3H 12.7v

Thanks for your reply, I appreciate it.
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Hello,

I recently acquired a faulty [B]Macbook Air 2019 A1932[/B] with mainboard[B] 820-01521-A[/B].

Seller claimed that device just stopped working suddenly.

Device does not boot or give any signal of life other than the white led on mainboard.
Using cheap multimeter and microscope I went trough list of semi-random diagnostic steps:

[B]Voltage measurements[/B]

[B]Charger in USBC-B (closer to display) everything disconnected.[/B]

PP20V_USBC_XB_VBUS 20.7v
PP3V3_UPC_XB_LDO 3.25v
PP1V8_UPC_XB_LDOA 1.81V...

Hi, I'm a tinkerer and electronics hobbyist who tries to fix things - sometimes with success.