[ROOT]+[Install CWM recovery]+[Install any ROM]

do step by step these Instructions for flashing any ROM on GT-P1000 :

1- first you must install Samsung USB drivers from attachment

2- then you must root your device
you can root p1000 2.3.X with DoomLord V4
download Doomlord then extract into your pc
set your device in USB debugging mode then connect via usb cable into pc
go to folder and run as administrator mode "runme.bat" file
press any key and waiting until your device restarts
if you see "SuperUser" icon in apps root be successful

3- galaxy tab p1000 is an old android device so you cannot flash cwm recovery with "Rom Manager"
you must flash recovery with odin
download Odin 3 v1.7
download recovery file "http://www.mediafire.com/?q8s0wnj1s6109gc"
open odin and unchecked "Re-partion" *** if u check this maybe brick your device!!
http://xdaforums.com/attachment.php?attachmentid=2230439&stc=1&d=1378154387

click on PDA and open recovery file that you download
turn off your device
then hold volume- with power button , go to downloading mode
connect tablet via usb to pc , waiting for installing drivers
goto odin if you see yellow COM text its ok ,,
click on START button and waiting until restarting your device
now recovery cwm is installed

4- download your favorites rom and copy it into your sd card folder

5- turn off the device and hold volume+ with power button for 10-15 sec

up = volume +
down = volume -
select = power

Make a Nandroid backup before you install the new ROM.

go to wipe cash and do it
go to factory reset and do it
go to advanced and wipe calvik and wipe battery stat
then go back and select install zip from sd card
select your ROM file and tap power button , wait for installing rom
after you see Successful text you can reboot device and Enjoy from your new ROM

if you see this error : install aborted (status 7)
go to mount and storage then unmount "/system"
then format "/system" and "/data"
try again and it will be ok !!

View attachment Odin3_v1.7.rar
View attachment DooMLoRD_v4.zip

Use overcome method. Follow my signature.

Sent from my GT-P1000 using xda app-developers app

I completed step 3, it said that all completed but now it is stuck in a restart loop, it shows some error colors (see image), then it shows Samsung logo, vibrates 3-4 times and it restarts again.
I cannot seem to get it recovery mode (UP+Power), download mode enters OK (Down+Power).
Any ideas ?