Can't upload to Pro Micro

I actually managed to fix this just after I finished typing it, by shorting RST just as it said uploading. The first time it immediately failed, saying it couldn’t connect to COM5, which was strange as the only port showing before was COM1 and that’s what I’d selected and checking Device Manager it still showed the driver-less “USB IO Board” but on the second attempt it installed a driver and now that device has changed to “Arduino Leonardo (COM6)” and it’s ID has changed to “USB\VID_2341&PID_8036&REV_0100&MI_00”.

Anyway, I’ll post this anyway in case anyone has any advice about what happened and what the correct steps are if it happens again. It might also be useful to someone else who runs into the same problem.


So I’ve got a Pro Micro 5v/16Mhz and it’s been working OK until now. I’m using Windows 8 now and it was working fine under that but it seems an upload went bad and now when I try and upload to it, it just gets stuck on Uploading for ages before eventually throwing up:

Found programmer: Id = “B¥Õ”; type =

Software Version = . ; Hardware Version = .

avrdude: error: buffered memory access not supported. Maybe it isn’t a butterfly/AVR109 but a AVR910 device?

I’m using the correct board profile downloaded from https://www.sparkfun.com/products/12640 and there’s only one COM port, COM1.

However, now something else has happened and Device Manager shows a device “USB IO Board” which is missing a driver, as well as COM1 when I connect the board.

I’ve checked the VID/PID for this device and it’s VID_1B4F&PID_9206 which isn’t in the .inf with the drivers that come with arduino-.1.5.7. The ones that come with 1.0.5-r2 have, under [DeviceList.NTamd64]

%promicro.bootloader.name%=DriverInstall, USB\VID_1B4F&PID_9206

%promicro.sketch.name%=DriverInstall, USB\VID_1B4F&PID_9206&MI_00

but I think I probably added that myself a while ago to get it to install. Anyway, if I try and install the driver with the 1.0.5-r2 files, it says it found driver software for the device ‘but encountered an error whilst attempting to install it. %promicro.sketch.name%. The hash for the file is not present in the specified catalogue’. If I add those two lines to the 1.5.7 inf file, I get the same error trying to install with those drivers. If I try and install with the .inf file that comes with the device profile files, under SF32u4_boards-master/driver, which does list USB\VID_1B4F&PID_9206&MI_00 then I get ‘The third-party INF does not contain digital signature information’.

I’ve tried shorting RST to GND to put it in bootloader mode but I don’t see any lights flash or anything to indicate it’s done anything. I’ve tried double-tapping (well, double-shorting) it as well to put it in bootloader mode for 8s but again I don’t get any indication it’s done anything. Actually, if I just short it once, after about 8s the yellow light does flash, so it does appear to be doing something but it doesn’t help and the software is still stuck on Uploading for ages before throwing the same error.