Sounds like you’ve gotten this as close to a confirmed board issue as you can (I suspect you’re right).
-
Well. The thing about the iPhone 7 is it loves a good boot loop. Could definitely be audio IC, especially with the drop, but the unfortunate thing about the lines that are typically problematic with Audio IC is that the problem spots can be tricky to get at for testing. And reflow could help, but more than likely if that’s the issue, you’re gonna need a crash course in BGA work. I use the method Jesse Cruz outlines at [link|https://repair.wiki/w/IPhone_7|repair.wiki|new_window=true] for these (you’re have to scroll to the Audio IC section). Based on your 19% fail on restore though, I might look into NAND issues.
+
Well. The thing about the iPhone 7 is it loves a good boot loop. Could definitely be audio IC, especially with the drop, but the unfortunate thing about the lines that are typically problematic with Audio IC is that the problem spots can be tricky to get at for testing. And reflow could help, but more than likely if that’s the issue, you’re gonna need a crash course in BGA work. I use the method Jesse Cruz outlines at [link|https://repair.wiki/w/IPhone_7|repair.wiki] for these (you’ll have to scroll to the Audio IC section). Based on your 19% fail on restore though, I might look into NAND issues.
NAND power line shorts are super common, especially after a drop. They don’t usually boot loop for that, they just won’t boot. But I would look anyways. I would carefully scrape away the silicone over some of the components around the NAND just probe around for shorts (especially in the corners, for some reason). It’s just a thing that happens on tons of iPhones, heavy drop cracks a cap and then NAND can’t get the right power.
-
Having a DC power supply, or a [link|https://www.mobilesentrix.com/dt880-mobile-phone-current-maintenance-tester-for-iphone-6p-to-x|DT880|new_window=true] (those can be had at eBay or other spots too, just linking for point of reference) can help to an extent, but interpreting boot loop power signatures is a science, and an in exact one at that. It’s a lot of pattern recognition, which means exposure to a lot of patterns.
+
Having a DC power supply, or a [link|https://www.mobilesentrix.com/dt880-mobile-phone-current-maintenance-tester-for-iphone-6p-to-x|DT880] (those can be had at eBay or other spots too, just linking for point of reference) can help to an extent, but interpreting boot loop power signatures is a science, and an inexact one at that. It’s a lot of pattern recognition, which means exposure to a lot of patterns.
I wanted to get this posted before I forget so I probably left some stuff out, but I figured this is a start
Sounds like you’ve gotten this as close to a confirmed board issue as you can (I suspect you’re right).
Well. The thing about the iPhone 7 is it loves a good boot loop. Could definitely be audio IC, especially with the drop, but the unfortunate thing about the lines that are typically problematic with Audio IC is that the problem spots can be tricky to get at for testing. And reflow could help, but more than likely if that’s the issue, you’re gonna need a crash course in BGA work. I use the method Jesse Cruz outlines at [link|https://repair.wiki/w/IPhone_7|repair.wiki|new_window=true] for these (you’re have to scroll to the Audio IC section). Based on your 19% fail on restore though, I might look into NAND issues.
NAND power line shorts are super common, especially after a drop. They don’t usually boot loop for that, they just won’t boot. But I would look anyways. I would carefully scrape away the silicone over some of the components around the NAND just probe around for shorts (especially in the corners, for some reason). It’s just a thing that happens on tons of iPhones, heavy drop cracks a cap and then NAND can’t get the right power.
Having a DC power supply, or a [link|https://www.mobilesentrix.com/dt880-mobile-phone-current-maintenance-tester-for-iphone-6p-to-x|DT880|new_window=true] (those can be had at eBay or other spots too, just linking for point of reference) can help to an extent, but interpreting boot loop power signatures is a science, and an in exact one at that. It’s a lot of pattern recognition, which means exposure to a lot of patterns.
I wanted to get this posted before I forget so I probably left some stuff out, but I figured this is a start