HTC was chosen to manufacture the Xperia X1, predecessor to the X2, but has now been ousted from the partnership with Sony Ericsson.
Sony Ericsson cited problems with quality as the reason for switching its choice of manufacturer.
Rumours suggest that three companies are in the running to win the contract for the X2, including Foxconn International and Asus-owned Pegatron.
Sony Ericsson’s partner of choice is expected to be announced sometime in the first quarter, with the Windows Mobile-based X2 to be released by the end of 2009.
The Xperia X1 has been on sale in the UK since September.