USB power detection failure

[sudharsan]

I am using custom board nRF52820. I'd done OTA up-gradation with USB connected. Firmware successfully updated on device over BLE and device got soft reset.

After removal of USB, device did not detected USB removal.

Queries:

1. Can we do OTA over BLE with USB connected ?

2. After the soft reset what are all the registers retained ?

3. Why did USB power removal not detected after OTA over BLE ?

[OlishaDoon]

About 1st one;
www.cypress.com/.../download

[sudharsan]

Thanks for your reply. But I don't think the document is relevant for my 1st query.

I have connected USB connection ( means charging the device ) during OTA update.

1. Can we do OTA over BLE with USB connected (while charging the device) ?

2. After the OTA updation, soft reset would occur. So due to soft reset what are all the registers retained ?

3. Why did USB power removed case, not detected after soft reset (after OTA updation)?

Note:

It is requested that all the three are important for me to resolve.