I don't know if it's worth stickying this but I've recently had an interesting experience regarding an Erisin double din head unit. I've had a number of Erisin units and they've all been very good, and I can't recommend them enough.
My friend recently asked me to help him buy a double din head unit as his OEM console failed. I suggested Erisin due to their features and seemingly good reliability. I've had 4 now, and not a single one has failed (which is odd considering all I read on the Internet is how China 2Din's fail ). We had a trawl through second hand on eBay as my friend was a tiny bit reluctant to spend too much, but I found a unit listed for Spares/Repair for pretty cheap.
The listing description stated that the SD card reader was broken. Apparently neither the Sat Nav worked, nor the SD Music played because the SD card reader had been broken since Day 1 and Erisin refused to replace it as they'd received it twice and both times it had worked correctly in their factory. I could tell there was an element of anger in this guys writing. Anyway, I was quite confused by the listing, see, there are two SD card readers per unit, not one. The audio side of the unit has an SD card reader, which is linked to the main DVD player which is how it plays music, then there is another SD card reader linked the WinCE Mainboard and gives you access to the maps. Is it likely, or even possible that BOTH would have broken? Almost certainly not...
We bought the device at a heavily discounted price due to the supposed broken SD Card reader. My friend said that if the device was genuinely broken, he would use it for the CD/DVD functionality, it's still a good price after all. The device arrived with two SD cards inserted into the unit. We plugged it in and sure enough, the SD Music refused to play. The first song would start and roughly 5 seconds in, the internal software running the DVD player (which has the SD support) would reset and then resume from the beginning of the song. Sat Nav yielded bad results as well. After maybe 30 seconds of running iGo8, the WinCE ROM would throw a Chinese looking error with the name of a bmp file. Each time the bmp was different. Straight away, I figured that the software was simply botched, so I loaded a fresh version of iGo Primo, but this didn't improve the situation. 5 minutes into simulating a navigation, another error was thrown (memory error), and the nav unit simply reset.
I examined the SD Card's that came with the device and quickly noticed something odd. They were both 'SanDisk', but they didn't look genuine whatsoever. I'm not a SanDisk salesman, or enthusiast, but I know what a SanDisk SD card looks like, and not only did the logo look wrong, but there was no indication of the Class (on either) and there was no serial number on the back which SanDisk are known to supply all their memory with. We took a trip down the shops and bought two genuine 8GB SanDisk SD cards. We loaded the first one with music and the second one with a fresh copy of iGo Primo 2.4 with all the latest maps.
The result?
Perfect navigation with no errors, and a SMS Text Message from my friend saying "been listening to the music on way to work this morning, working perfectly".
Clearly both the SD cards supplied by Erisin were not up to scratch. I've never had a problem myself with the SD cards supplied by Erisin, but I assume they purchase these from local suppliers and perhaps this was a bad batch. My advice would be consider replacing all supplied SD cards when your device arrives as you can't be guaranteed of the quality! It'll save you selling it on eBay and losing £100 (in the case of the unfortunate fellow who sold it to us).
Hope this helps anyone thinking of binning their device due to SD issues.