No problem. I measured 2.73V on the Kindle's TX rail, so I went with that and a few 100Ohm resistors in series to be safe. Serial parameters are probably 115200 baud, as this is a standard baudrate.
I actually got output and managed to enter uboot and some sort of recovery/developer menu. It looks like I can flash new files trough the serial link
Attached is a log from the start of factory reset (just before entering 'RESET') until the after the first complete boot. The relevant section doesn't seem very helful however, all I see is a system call that crashes:
Code:
INIT: Switching to runlevel: 5
INIT: Sending processes the TERM signal
system: I S30network:def:initializing network configuration
system: I wancontrol:pc:processing "wanon"
mount: usbfs already mounted or /proc/bus/usb busy
mount: according to mtab, usbfs is already mounted on /proc/bus/usb
waninfo 0.6.2 Copyright (C) 2008, 2009 Amazon Technologies, Inc. All rights reserved.
modemcmd 0.3.2 Copyright (C) 2008, 2009 Amazon Technologies, Inc. All rights reserved.
system: I wancontrol:pc:processing "wanoffkill"
system: I S60dbus:def:starting system message bus
Starting Process Monitoring Daemon: Starting Power Management Daemon: system: I S70netwatchd:def:starting Netwatch Daemon
system: I S70wand:def:starting WAN daemon
Unable to handle kernel paging request at virtual address 4002a000
pgd = c5d58000
[4002a000] *pgd=85d24031, *pte=00000000, *ppte=00000000
Internal error: Oops: 817 [#1] PREEMPT
Modules linked in: ehci_hcd mma7660F mxc_keyb uinput fuse g_file_storage arcotg_udc charger mwan usbcore eink_fb_shim eink_fb_hal_broads eink_fb_hal fiveway
CPU: 0 Not tainted (2.6.22.19-lab126 #3)
PC is at v6_coherent_kern_range+0x4/0x24
LR is at arm_syscall+0x1f0/0x348
pc : [<c00ac768>] lr : [<c00a91d0>] psr: 80000013
sp : c66d7e80 ip : c66d7e80 fp : c66d7fa4
r10: 40051fec r9 : c66d6000 r8 : 00000000
r7 : 000f0002 r6 : 00000000 r5 : 4004a000 r4 : 40026000
r3 : c0339fe8 r2 : 00000000 r1 : 4004a000 r0 : 4002a000
Flags: Nzcv IRQs on FIQs on Mode SVC_32 Segment user
Control: 00e5387f Table: 85d58000 DAC: 00000015
Process wand (pid: 1890, stack limit = 0xc66d6260)
Stack: (0xc66d7e80 to 0xc66d8000)
7e80: c6f29a30 000000a4 c66d7eac c66d7e98 c01b086c c00c102c 00000002 c7c0cbd4
7ea0: c66d7ebc c66d7eb0 c00df4a4 c01b07c8 c66d7efc c66d7ec0 c00aa5a0 c00df4a0
7ec0: 0000003a c66d3560 c66d7f04 c66d7ed8 c028e83c c00c102c c0323d60 00000017
7ee0: c66d7f14 c66d7ef0 c01b09dc c00c102c 00000024 00000000 c5d06230 c5d24924
7f00: 4004a000 00000000 c66d7f24 c66d7f18 c00df490 c01b089c c66d7fa4 c66d7f28
7f20: c0102a6c c00df48c 00100075 c7c3fce8 c7805d00 00000000 00000000 c00c102c
7f40: 00100073 00000005 4004a000 4004a000 00000024 c7c0cba0 c5d59000 c66d6000
7f60: 0000005f 00000000 c5d59000 4004a000 c00cb5e8 c5d06230 c032a6f8 40020018
7f80: bee82a88 40026000 0000007d 40020018 bee82a88 40026000 00000000 c66d7fa8
7fa0: c00a4ec0 c00a8fec 40020018 bee82a88 40026000 4004a000 00000000 00000015
7fc0: 40020018 bee82a88 40026000 000f0002 40029044 00000000 40051fec bee82b4c
7fe0: 00000015 bee82a78 4000c884 4000c8a0 60000010 40026000 00000000 00000000
Backtrace:
[<c00a8fe0>] (arm_syscall+0x0/0x348) from [<c00a4ec0>] (ret_fast_syscall+0x0/0x2c)
r6:40026000 r5:bee82a88 r4:40020018
Code: eaffffe8 e1a0f00e e1a0f00e e3c0001f (ee070f3a)
reboot: I def:pcut::arch_reset
reboot: I def:pcut::mx31_deep_reset
reboot: I def:pcut::pmic_power_set_pc_config