Chosen Solution
After update to 10.3.3. (via ota) there’s no modem firmware and always searching (imei is OK), then restart after some minute. I’ve restored (via itunes) with same 10.3.3, then everything is OK, but after 2 days, when i insert sim (ipad in airplane mode) the same things happened : searching & no modem firmware. It was working well for 5 years, now my ipad is useless.
Such type of fault mostly appear after the force brick.This actually happen when baseband chip is not working as well or damage.If you have idea to open search on ifix it and rehot the baseband chip or search for faulty parts near baseband chip.If the problem is still same you have to replace it.
