Reports of other flags seen in Tibet

I have an history book of Tibet by Laurent Deshaies, and it is said that in 1913, the Dalai Lama came back to Lhasa after a short Chinese invasion in reply to the English attempts to extend their sphere of influence. The Chinese troops were left to their fate by the old empire and then expelled from Tibet.

The new "independent" country began with creating a national army with the help of English, Russian and Japanese officers. These troops paraded with the first national flag which was "crimson with an embroidered lion", according to Alexandra David-Neel, the first western woman who had entered into Lhasa in 1914.
Corentin Chamboredon, 20 May 2004

In the movie "Seven Years in Tibet" there are many supposed images of Lhasa, and in many parts of the city are flown an unknown flag, probably the local flag. It is horizontally blue, yellow and red horizontal, with two white stars in the upper stripe.
Jaume Ollé, 22 January 1998

Although I have no confirmation of this, I have heard tell of a white flag with either one or two snow lions in the center. The snow lion is a symbol on the standard Tibetan flag, and could well be used for other banners. However, the place to inquire may well be the Tibetan Government in Exile.
Thomas Robinson, 31 January 1998

On flickr there is an image of a flag which is apparently used by the Qomolangma Feng National Nature Reserve. Qomolangma 珠穆朗玛峰 is the Chinese transcription of the Tibetan name Jomolangma ཇོ་མོ་གླང་མ, i.e. Mount Everest.

The upper half of flag shows the shape of the mountain in light blue and white (the white parts being the snow, I guess). The lower half, which is surrounded by a black line, is white and shows three lines of text in different scripts : Nepalese (Mount Everest is on the border between Nepal and China), Chinese and English. The last line is partially hidden, but we can read the words "...angma National Nature Preserve" [sic]. On the lower fly, there is a black stupa inside a black circle.
Corentin Chamboredon, 29 November 2008