[AT&T Samsung Galaxy S II SGH-I777] pokey9000:
It should be 301 kiloohms.. I can verify that this works.

FWIW, the Factory UART mode at 619k works as well. Here's a log (some bits redacted). The SBL command prompt is there as well.

Welcome to Samsung Primitive Bootloader.
build time: Aug 27 2011 04:53:51
current time: 7e/f/7 3f:7b:15

[set_mmc_ocr] Sector Mode
[hsmmc_init] MMC card is detected
Product Name : VYL00M
<display_card_info:1009> ext_csd
<display_card_info:1011>card_size: 15028
Total Card Size: 15029 MByte

mmc_init: card initialization completed!
pbl found bootable sbl in #49152.
jump to sbl 0x4d400000.

Secondary Bootloader v3.1 version.
Copyright (C) 2011 System S/W Group. Samsung Electronics Co., Ltd.
Board: C1 REV 02 / Aug 27 2011 04:53:57
current time: 7e/f/7 3f:7b:15

booting code=0xc0d080c0
[set_mmc_ocr] Sector Mode
[hsmmc_init] MMC card is detected
Product Name : VYL00M
CID:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
<display_card_info:1040> ext_csd
<display_card_info:1042>card_size: 15028
Total Card Size: 15029 MByte

Total Sector Count: 30777344

MoviNand Initialization Complete!
===== PARTITION INFORMATION =====
ID : GANG (0x0)
DEVICE : MMC
FIRST UNIT : 0
NO. UNITS : 0
=================================
ID : BOOT (0x1)
DEVICE : MMC
FIRST UNIT : 0
NO. UNITS : 0
=================================
ID : EFS (0x4)
DEVICE : MMC
FIRST UNIT : 8192
NO. UNITS : 40960
=================================
ID : SBL1 (0x2)
DEVICE : MMC
FIRST UNIT : 49152
NO. UNITS : 2560
=================================
ID : SBL2 (0x3)
DEVICE : MMC
FIRST UNIT : 53248
NO. UNITS : 2560
=================================
ID : PARAM (0x5)
DEVICE : MMC
FIRST UNIT : 57344
NO. UNITS : 16384
=================================
ID : KERNEL (0x6)
DEVICE : MMC
FIRST UNIT : 73728
NO. UNITS : 16384
=================================
ID : RECOVERY (0x7)
DEVICE : MMC
FIRST UNIT : 90112
NO. UNITS : 16384
=================================
ID : CACHE (0x8)
DEVICE : MMC
FIRST UNIT : 106496
NO. UNITS : 512000
=================================
ID : MODEM (0x9)
DEVICE : MMC
FIRST UNIT : 618496
NO. UNITS : 32768
=================================
ID : FACTORYFS (0xa)
DEVICE : MMC
FIRST UNIT : 651264
NO. UNITS : 1048576
=================================
ID : DATAFS (0xb)
DEVICE : MMC
FIRST UNIT : 1699840
NO. UNITS : 4194304
=================================
ID : UMS (0xc)
DEVICE : MMC
FIRST UNIT : 5894144
NO. UNITS : 23826432
=================================
ID : HIDDEN (0xd)
DEVICE : MMC
FIRST UNIT : 29720576
NO. UNITS : 1048576
=================================
loke_init: j4fs_open..success
<start_checksum:1033>CHECKSUM_HEADER_SECTOR :42
<start_checksum:1035>offset:42, size:1024
Not Need Movinand Checksum
load_lfs_parameters valid magic code and version.
switch_sel_str='1'
load_debug_level: read debug level successfully(0x574f4c44)...LOW
init_ddi_data: usable ddi data.
fuelgauge_implementaion - start
fuelgauge_implementaion - end
fuel_gauge_get_version: [1]=0, [0]=92
init_fuel_gauge: vcell = 3723 mV, vfocv = 3781 mV, soc = 36
microusb_get_attached_device: STATUS1:0x3d, 2:0x0
microusb_get_attached_device: STATUS1:0x3d, 2:0x0
3054 = (370300 - 363902)*47744/100000
[8] 376967 = (3054 * 100000) / 57200 + 371628
init_microusb_ic: MUIC: CONTROL1:0x1b
init_microusb_ic: MUIC: CONTROL1:0x1b
init_microusb_ic: MUIC: CONTROL2:0x3a
init_microusb_ic: MUIC: CONTROL2:0x3a
reading nps status file is successfully!.
nps status=0x504d4f43
PMIC_IRQSRC = 0x0
PMIC_IRQ1 = 0x3
PMIC_IRQ2 = 0x1b
PMIC_IRQ3 = 0x0
PMIC_IRQ4 = 0x11
PMIC_STATUS1 = 0x0
PMIC_STATUS2 = 0x17
PMIC_STATUS3 = 0x0
PMIC_STATUS4 = 0x0
bootloader base address=0x4d400000
LPDDR0 1st. cached=0x40000000, size=0xe400000
LPDDR0 non-cached=0x4e400000, size=0xa00000
LPDDR0 2nd. cached=0x4ee00000, size=0x1200000
RST_STAT = 0x10000
get_hwrev() = 14
board_process_platform: MAGIC c0d080c0 at 40000000!
microusb_get_attached_device: STATUS1:0x3d, 2:0x0
microusb_get_attached_device: STATUS1:0x3d, 2:0x0
microusb_get_attached_device: STATUS1:0x3d, 2:0x0
microusb_get_attached_device: STATUS1:0x3d, 2:0x0
hw_pm_status: jig_status = 1, chg_status = 0
DISPLAY_PATH_SEL[MDNIE 0x1]is on
div:2, FB_SOURCE_CLOCK:667000000, FB_PIXEL_CLOCK:25067520
MDNIE setting Init start!!
vsync interrupt is off
video interrupt is off
[fb0] turn on
MDNIE setting Init end!!

Autoboot (0 seconds) in progress, press any key to stop
boot_kernel: debug level low!
checkbit: find RECOVERY
checkbit (0)
......ATAG_CORE: 5 54410001 0 0 0
MEMCONFIG: 20e01323 20e01323
ATAG_MEM: 4 54410002 10000000 40000000
ATAG_MEM: 4 54410002 10000000 50000000
ATAG_MEM: 4 54410002 10000000 60000000
ATAG_MEM: 4 54410002 10000000 70000000
ATAG_SERIAL: 4 xxxxxxxxxxxxxxxxxxxxxxxxxxxx
ATAG_REVISION: 3 54410007 e
ATAG_CMDLINE: 37 54410009 'loglevel=4 console=ram sec_debug.enable=0 sec_debug.enable_user=0 c1_watchdog.sec_pet=5 sec_log=0x100000@0x5ea00000 s3cfb.bootloaderfb=0x5ec00000 ld9040.get_lcdtype=0x2 consoleblank=0 lpj=3981312 vmalloc=144m'
ATAG_NONE: 0 0

Starting kernel at 0x40008000...