APX MODE driver and stuck in APX mode issues
Tab is an acer iconia a500 8gb version running CWM, and HC bootloader. Last ROM on honeycomb was flexreaper but I forget version. I hadn't used tab in a while.
I wanted to let you know how I resolved it. I spent 2 days trying to upgrade to ICS bootloader and touch recovery. I almost gave up with a partial brick of a tab. I was no longer able to boot a ROM but could get to APX mode (sort of APX mode) where screen was black and power LED was on by using manual process. Hold in power and Reset for 3 seconds then release power while holding reset for another second. Tab would be recognized as APX mode device by the computer and flash tools but I couldn't get any of the tools to do the flashing. Blackthunder and nvflash failed with various errors. I found out after hours of trying this was not really APX mode. See below.
1. To fix USB driver issue. I had to install the Naked USB driver and Google USB driver from SDK package. All links found here on XDA. Only at this point did the tab show as a valid working APX device in devices and printers. Drivers still showed as unknown but worked. In Device manager was showing under USB host controller as acer usb recovery device or something like that.At this point I had all drivers installed. Acer driver, Google USB, and naked driver. I installed in that order until device was working on win 7 x64.
2. APX mode is described in some places as blank screen with power LED on but this is like stage one of apx mode. You still need the tool (nvflash or blackthunder) to get you to the point where the screen says APX mode in white font in the left upper corner and you are truely in APX mode. Use the auto process in the tool until you get there. My tab also had the word acer in large green font in the middle of the LCD when in true APX mode. I was never able to get to full APX mode using manual APX process on tab. This seems to place the tab in an APX ready state. Then you can use nvflash, a500manager, or blackthunder auto tools to get to full apx mode. Tab does a quick reboot or something and vibrates when going from APX ready to full APX mode with the screen going from blank to where it says apx mode in small white letters and acer in green large font (middle of screen). After I was in APX mode The only thing that worked was BABSECTOR or BADSECTOR tool to flash it. I ran the a501a.bat and then the a501b.bat inside the extracted folder to get ICS V8 bootloader and touch recovery installed. Once I used the BADSECTOR tool the process was quick and flashed in a matter of a few minutes. In 2 minutes I had completed what was going on for almost 2 days. Wow! I almost gave up. You can edit the script or just insert your SBK at the prompt.
I found the BAD or BABSECTOR process listed in a short post comment on another forum using google searches. There wasn't a lot of detail. Just the order of file use and that it it worked for someone who was having similar issues. You obviously need your SBK.
Hope this helps someone. Good luck!
Auto signature below is wrong. I had changed to flexreaper ROM.
CWM Recovery 1.3.4
ROM: [ICS4.0.3] Taboonay 3.0.1