Weird upload behavior?

[mbolivar]

CDC_ACM mode stopped working for Perry, even when reverting to a known good version of libmaple. He could upload code via DFU by manually resetting and uploading during the window, but programs would fail (with no fault indication) immediately. Simply unplugging/replugging solved the problem (with the program in FLASH). This was with the FLASH memory target.

Here's the dmesg (not-working and then working):

[148682.090090] usb 6-2: new full speed USB device using uhci_hcd and address 121
[148682.255290] usb 6-2: configuration #1 chosen from 1 choice
[148684.790128] usb 6-2: USB disconnect, address 121
[148743.890124] usb 6-2: new full speed USB device using uhci_hcd and address 122
[148744.055380] usb 6-2: configuration #1 chosen from 1 choice
[148746.790086] usb 6-2: USB disconnect, address 122
[148757.100128] usb 6-2: new full speed USB device using uhci_hcd and address 123
[148757.324387] usb 6-2: configuration #1 chosen from 1 choice
[148759.580218] usb 6-2: USB disconnect, address 123
[148760.320129] usb 6-2: new full speed USB device using uhci_hcd and address 124
[148760.484370] usb 6-2: configuration #1 chosen from 1 choice
[148763.040348] usb 6-2: USB disconnect, address 124
[148792.410121] usb 6-2: new full speed USB device using uhci_hcd and address 125
[148792.576377] usb 6-2: configuration #1 chosen from 1 choice
[148795.290201] usb 6-2: USB disconnect, address 125
[148795.610127] usb 6-2: new full speed USB device using uhci_hcd and address 126
[148795.778328] usb 6-2: configuration #1 chosen from 1 choice
[148795.781278] cdc_acm 6-2:1.0: ttyACM0: USB ACM device