2016-08-21 9:20 GMT-03:00 Luc Verhaegen <[email protected]>: > > On Sat, Aug 20, 2016 at 07:26:46PM -0700, Leonardo wrote: > > Hi. I'm building a very minimal Linux distro to use as an embedded system > > on a A20 tablet. I don't want to believe this, but I think that booting my > > distro has damaged the device. The tablet came with Android. I had it > > rooted so I could extract the fex file. Then I got kernel 3.4.104 and uboot > > 2016.02 from GitHub, built my file system with buildroot and so on. I'm > > using an SD card for now. So I tried booting my system and nothing came up > > on the LCD. Then I remove my SD card, try to get back to Android and still > > nothing on the screen! The device is not dead. I can access it using ssh > > over the wifi, the usb port works fine. Basically I can do anything > > remotely. At first I thought I might have damaged something on the PCB > > while performing the tests, so I had a second tablet. Boot on Android, > > display works fine. Boot on my distro, nothing on screen. Try to get back > > to Android, and nothing on the screen again. By the way, the backlight > > lights up as usual, so the display is not dead also. I've worked on a > > similar project last year and had no problem like this at all. I have no > > idea what went wrong. Is it possible that my kernel has damaged the device > > somehow? > > Damage, no. Ruined nand content due to different settings, yes. > > Thank allwinner for changing its mind on how to configure its nand > controller in the middle of the A20 lifetime, while having code in > its nand driver that clears the ram if it finds garbage. > > Luc Verhaegen.
That makes sense. I tried dumping /dev/nand and got 8GB of 0xFF. In addition to that, there's this message on boot: [NAND] nand driver version: 0x2 0x9 Dev Sunxi softw311 nand magic does not match for MBR 1: ▒▒▒▒▒▒▒▒ ... Dev Sunxi softw311 nand header bad for all MBR copies, MBR corrupted or not present. nand: unknown partition table [NAND]nand driver, ok. Last year I had this embedded system running on a 7" tablet. Now I'm trying the same using a 9" one. Both are A20 and from the same manufacturer. Actually the designs are quite similar, except for the screen size and some small changes on the PCB. So I got the system I'm currently setting up, changed its fex for the 7" one and gave it a try on the smaller tablet. I got everything on screen by the first run... Back to the 9" tablet, after changing back the fex file, and blank screen again... I was thinking before that I could have stripped down my kernel too much, and because of that the screen wasn't working, but now I don't know what to think... -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
